Levaquin 500 side effects


Levofloxacin, Oral Tablet

The levofloxacin dosage your doctor prescribes will depend on several factors. These include:

  • the type and severity of the condition you’re using levofloxacin to treat
  • your age
  • your weight
  • other medical conditions you may have, such as kidney damage

Typically, your doctor will start you on a low dosage and adjust it over time to reach the dosage that’s right for you. They’ll ultimately prescribe the smallest dosage that provides the desired effect.

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to suit your needs.

Forms and strengths

Generic: Levofloxacin

  • Form: oral tablet
  • Strengths: 250 mg, 500 mg, 750 mg

Dosage for pneumonia

Adult dosage (ages 18–64 years)

  • Nosocomial pneumonia (pneumonia caught in a hospital): 750 mg taken every 24 hours for 7 to 14 days.
  • Community-acquired pneumonia: 500 mg taken every 24 hours for 7 to 14 days, or 750 mg taken every 24 hours for 5 days. Your dosage will depend on the type of bacteria causing your infection.

Child dosage (ages 0–17 years)

This drug should not be used in children younger than 17 years for this condition.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dosage or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for acute bacterial sinusitis

Adult dosage (ages 18–64 years)

500 mg taken every 24 hours for 10–14 days or 750 mg taken every 24 hours for 5 days. Your dose will depend on bacteria causing the infection.

Child dosage (ages 0–17 years)

This drug should not be used in children younger than 17 years for this condition.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dosage or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for acute bacterial exacerbation of chronic bronchitis

Adult dosage (ages 18–64 years)

500 mg taken every 24 hours for 7 days.

Child dosage (ages 0–17 years)

This drug should not be used in children younger than 17 years for this condition.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dosage or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for skin and skin structure infections

Adult dosage (ages 18–64 years)

  • Complicated skin and skin structure infections (SSSI): 750 mg taken every 24 hours for 7 to 14 days.
  • Uncomplicated SSSI: 500 mg taken every 24 hours for 7 to 10 days.

Child dosage (ages 0–17 years)

This drug should not be used in children younger than 17 years for this condition.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dosage or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for chronic bacterial prostatitis

Adult dosage (ages 18–64 years)

500 mg taken every 24 hours for 28 days.

Child dosage (ages 0–17 years)

This drug should not be used in children younger than 17 years for this condition.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dosage or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for urinary tract infections

Adult dosage (ages 18–64 years)

  • Complicated urinary tract infection or acute pyelonephritis: 250 mg taken every 24 hours for 10 days or 750 mg taken every 24 hours for 5 days. Your dose will depend on the type of bacteria causing the infection.
  • Uncomplicated urinary tract infection: 250 mg taken every 24 hours for 3 days.

Child dosage (ages 0–17 years)

This drug should not be used in children younger than 17 years for this condition.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dosage or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for inhalational anthrax, post-exposure

Adult dosage (ages 18–64 years)

500 mg taken every 24 hours for 60 days.

Child dosage (ages 6 months–17 years)

  • Inhalational anthrax (post-exposure) in children who weigh 50 kg or greater: 500 mg taken every 24 hours for 60 days.
  • Inhalational anthrax (post-exposure) in children who weigh 30 kg to < 50 kg: 250 mg taken every 12 hours for 60 days.

Child dosage (ages 0–5 months)

This drug hasn’t been studied in children younger than 6 months. It shouldn’t be used in this age group.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dosage or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for plague

Adult dosage (ages 18–64 years)

500 mg taken every 24 hours for 10 to 14 days.

Child dosage (ages 6 months–17 years)

  • Plague in children who weigh 50 kg or greater: 500 mg taken every 24 hours for 10 to 14 days.
  • Plague in children who weigh 30 kg to < 50 kg: 250 mg taken every 12 hours for 10 to 14 days.

Child dosage (ages 0–5 months)

This drug hasn’t been studied in children younger than 6 months. It shouldn’t be used in this age group.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dosage or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

Special considerations

If you have kidney problems, your doctor will adjust your dosage and how often you take this drug. Your dosage will be based on how much your kidneys are damaged.

Levaquin Side Effects

Generic Name: levofloxacin

Medically reviewed by Drugs.com. Last updated on Jan 9, 2019.

  • Overview
  • Side Effects
  • Dosage
  • Professional
  • Tips
  • Interactions
  • More

Note: This document contains side effect information about levofloxacin. Some of the dosage forms listed on this page may not apply to the brand name Levaquin.

In Summary

More frequent side effects include: diarrhea and insomnia. See below for a comprehensive list of adverse effects.

WARNINGS: Levaquin may rarely cause tendon damage (such as tendinitis, tendon rupture) during or after treatment. Your risk for tendon problems is greater if you are over 60 years of age, if you are taking corticosteroids (such as prednisone), or if you have had a kidney, heart or lung transplant. Stop exercising, rest, and get medical help right away if you develop joint/muscle/tendon pain or swelling.

Levaquin should not be used in patients with myasthenia gravis. It may cause the condition to become worse. Seek immediate medical attention if you develop muscle weakness or trouble breathing.

For the Consumer

Applies to levofloxacin: oral solution, oral tablet

Other dosage forms:

  • intravenous solution


Oral route (Tablet; Solution)

Fluoroquinolones, including levofloxacin, are associated with disabling and potentially irreversible serious adverse reactions that have occurred together, including tendinitis and tendon rupture, peripheral neuropathy, and CNS effects. Discontinue levofloxacin and avoid use of fluoroquinolones in patients with these serious adverse reactions. Reserve use of levofloxacin for patients with no alternative treatment options for an uncomplicated UTI, acute bacterial exacerbation of chronic bronchitis, or acute bacterial sinusitis. Fluoroquinolones, including levofloxacin, may exacerbate muscle weakness in persons with myasthenia gravis. Avoid in patients with known history of myasthenia gravis.

Along with its needed effects, levofloxacin (the active ingredient contained in Levaquin) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking levofloxacin:

More common

  • Diarrhea


  • Agitation
  • blisters
  • confusion
  • diarrhea (watery and severe) which may also be bloody
  • feeling that others can hear your thoughts or control your behavior
  • fever
  • pain, inflammation, or swelling in the calves of the legs, shoulders, or hands, including tendon rupture or swelling of the tendon (tendinitis)
  • redness and swelling of the skin
  • seeing, hearing, or feeling things that are not there
  • sensation of burning on the skin
  • severe mood or mental changes
  • stomach cramps or pain (severe)
  • skin rash, itching, or redness
  • trembling
  • unusual behavior

Incidence not known

  • Black, tarry stools
  • blurred vision
  • burning, numbness, tingling, or painful sensation including peripheral neuropathy.
  • cough
  • dark urine
  • difficulty with breathing
  • difficulty with chewing, talking, or swallowing
  • drooping eyelids
  • fainting
  • fast or irregular heartbeat
  • general body swelling
  • hives
  • hoarseness
  • joint or muscle pain including tendon rupture or swelling of the tendon (tendinitis).
  • muscle cramps, spasms, pain, or stiffness
  • peeling or loosening of the skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • seizures
  • severe dizziness
  • severe tiredness
  • tightness in the chest
  • unsteadiness or awkwardness
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • vision changes
  • voice changes
  • weakness in the arms, hands, legs, or feet including worsening of myasthenia gravis.

Some side effects of levofloxacin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

  • Change in taste
  • constipation
  • dizziness
  • drowsiness
  • headache
  • lightheadedness
  • nausea
  • nervousness
  • stomach pain or discomfort
  • trouble sleeping
  • vaginal itching and discharge
  • vomiting

Incidence not known

  • Feeling of warmth or heat
  • flushing or redness of the skin, especially on the face and neck
  • sweating

For Healthcare Professionals

Applies to levofloxacin: compounding powder, intravenous solution, oral solution, oral tablet


The most frequently reported side effects with the IV and oral formulations included nausea, headache, diarrhea, insomnia, constipation, and dizziness. Therapy was discontinued due to side effects in 4.3% of patients overall (3.8% treated with 250 mg and 500 mg doses; 5.4% treated with 750 mg dose). The most common side effects leading to discontinuation were gastrointestinal (primarily nausea, vomiting), dizziness, and headache.

Cough/productive cough, dysgeusia, and fatigue/asthenia were reported most often with the nebulizer solution formulation.


During 1 study, C difficile-associated diarrhea occurred in 11 of 490 study patients (2.2%) receiving this drug.

Hemorrhagic diarrhea has been reported, which in very rare cases was indicative of enterocolitis (including pseudomembranous colitis).

Common (1% to 10%): Nausea, diarrhea, constipation, abdominal pain, dyspepsia, vomiting

Frequency not reported: Dry mouth, dysphagia, gastrointestinal hemorrhage, tongue edema, gastroesophageal reflux, melena, taste perversion, intestinal perforation, intestinal obstruction, C difficile-associated diarrhea, hemorrhagic diarrhea, enterocolitis

Nebulizer Solution:

-Common (1% to 10%): Nausea, vomiting, abdominal pain, diarrhea, constipation

-Uncommon (0.1% to 1%): Retching, dyspepsia, flatulence, oral fungal infection

Nervous system

Common (1% to 10%): Headache, dizziness

Rare (0.01% to 0.1%): Tinnitus

Frequency not reported: Abnormal coordination, coma, hypoesthesia, dysesthesia, weakness, involuntary muscle contractions, hyperesthesia, paralysis, speech disorder, stupor, encephalopathy, leg cramps, ataxia, migraine, seizures, benign intracranial hypertension, hearing loss, hearing impaired, peripheral sensory neuropathy/sensory axonal polyneuropathy, peripheral sensory motor neuropathy/sensorimotor axonal polyneuropathy, dyskinesia, extrapyramidal disorder, hypoglycemic coma

Postmarketing reports: Abnormal electroencephalogram (EEG), exacerbation of myasthenia gravis, anosmia, ageusia, parosmia, encephalopathy (isolated reports), pseudotumor cerebri, hypoacusis, peripheral neuropathy (sometimes irreversible)

Nebulizer Solution:

-Very common (10% or more): Dysgeusia (30%)

-Common (1% to 10%): Headache, dizziness, tinnitus

-Uncommon (0.1% to 1%): Hyposmia, somnolence, hearing loss

Cases of sensory or sensorimotor axonal polyneuropathy (affecting small and/or large axons) resulting in paresthesias, hypoesthesias, dysesthesias, and weakness have been reported.

One survey reported 33 cases of peripheral neuropathy associated with this drug, ranging in severity from mild and reversible to severe and persistent. In 1 case, a 51-year-old female developed “electrical” sensations, numbness, allodynia, multiple severe tendinitis, partial tendon rupture, impaired memory, confusion, and impaired concentration, with some symptoms persisting after 1 year.


Attempted or completed suicide reported, especially in patients with medical history of/underlying risk factor for depression.

Common (1% to 10%): Insomnia

Rare (0.01% to 0.1%): Psychotic reactions (with hallucination, paranoia)

Frequency not reported: Aggressive reaction, delirium, emotional lability, impaired concentration, manic reaction, mental deficiency, toxic psychoses, withdrawal syndrome, psychotic disorders/reactions with self-endangering behavior (including suicidal ideation, suicide attempt)

Postmarketing reports: Psychosis, paranoia, suicide attempt (isolated reports), suicidal ideation (isolated reports), completed suicide (isolated reports)

Nebulizer Solution:

-Common (1% to 10%): Insomnia

-Uncommon (0.1% to 1%): Anxiety, depression


Mucocutaneous reactions have been reported, sometimes after the first dose.

A 78-year-old female developed toxic epidermal necrolysis 2 days after parenteral therapy. The rash initially manifested as an erythematous rash, blistering, and mucosal sloughing but progressed to exfoliation involving three-quarters of the patient’s body surface area including mucosa. A positive Nikolsky sign was noted.

A 15-year-old male developed fatal toxic epidermal necrolysis taking this drug for 9 days. The rash progressed over 40 hours to involve 80% of his body surface area with a positive Nikolsky sign and involvement of the eyes and oral, nasal, and perianal mucosa.

Common (1% to 10%): Rash, pruritus

Uncommon (0.1% to 1%): Urticaria, hyperhidrosis

Rare (0.01% to 0.1%): Angioedema

Frequency not reported: Dry skin, skin disorder, skin exfoliation, skin ulceration, erythematous rash, alopecia, maculopapular rash, erythema nodosum, eczema, mucocutaneous reactions

Postmarketing reports: Photosensitivity/phototoxicity reaction, bullous eruptions (including Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis, fixed drug eruptions, erythema multiforme), leukocytoclastic vasculitis

Nebulizer Solution:

-Common (1% to 10%): Rash

-Uncommon (0.1% to 1%): Urticaria, pruritus


Achilles tendon rupture occurred in 4 of 489 study patients (3217 treatment days) after 1 to 10 days of this drug.

Severe rhabdomyolysis occurred in a 77-year-old female after 6 days of oral therapy. She developed acute renal failure (serum creatinine 678 micromole/L), hyperkalemia (6.8 micromole/L), anuria, elevated creatine kinase (30,400 international units/L), myoglobinemia (86,000 mcg/L), and acute hepatic cytolysis (AST 555 international units/L, ALT 249 international units/L). The fluid/electrolyte disorders and creatine kinase and myoglobin levels improved with hemodialysis; however, the patient died of a myocardial infarction and respiratory failure after 13 days.

Uncommon (0.1% to 1%): Arthralgia, myalgia, skeletal pain, tendinitis

Rare (0.01% to 0.1%): Tendon disorders (including tendinitis ), muscular weakness

Frequency not reported: Arthritis, arthrosis, pathological fracture, osteomyelitis, synovitis , back pain, ligament rupture

Postmarketing reports: Tendon rupture (e.g., Achilles tendon), muscle injury (including rupture), increased muscle enzymes, rhabdomyolysis

Nebulizer Solution:

-Common (1% to 10%): Arthralgia, myalgia

-Uncommon (0.1% to 1%): Tendinitis, costochondritis, joint stiffness


Ventricular arrhythmia and torsade de pointes have been reported, mainly in patients with risk factors of QT prolongation.

This drug was associated with 13 cases of torsade de pointes reported to the FDA between 1996 and 2001.

An 88-year-old woman developed a prolonged QTc interval during treatment with this drug (500 mg once a day). The QTc interval increased from 450 msec to 577 msec by the fourth day of treatment. This drug was discontinued after the patient experienced runs of ventricular tachycardia. The QTc interval then decreased to 437 msec 2 days after discontinuing this drug.

A 65-year-old woman with hypokalemia (2.8 mEq/L), hypomagnesemia (1.5 mEq/L), and renal insufficiency (serum creatinine 7.7 mg/dL, BUN 34 mg/dL) developed a QTc interval of 605 ms (baseline 435 to 485 ms), several episodes of torsade de pointes, and cardiac arrest after 3 days of this drug (250 mg/day IV). The QTc interval decreased to 399 ms and no further arrhythmias occurred after discontinuation of this drug and electrolyte replacement.

Hypotension has been associated with rapid or bolus IV infusion.

Common (1% to 10%): Phlebitis

Uncommon (0.1% to 1%): Cardiac arrest, palpitation, ventricular arrhythmia, ventricular tachycardia

Rare (0.01% to 0.1%): Tachycardia, hypotension

Frequency not reported: Angina pectoris, arrhythmia, atrial fibrillation, bradycardia, cardiac failure, cerebrovascular disorder, circulatory failure, coronary thrombosis, heart block, hypertension, aggravated hypertension, myocardial infarction, postural hypotension, purpura, supraventricular tachycardia, deep thrombophlebitis, vasculitis, ventricular fibrillation

Postmarketing reports: Vasodilation, QT interval prolongation/prolonged ECG QT, torsade de pointes

Nebulizer Solution:

-Uncommon (0.1% to 1%): Tachycardia, prolonged ECG QT


Decreased weight was reported during clinical trials for the nebulizer solution, but was primarily considered disease-related rather than drug-related.

Common (1% to 10%): Chest pain, edema, moniliasis

Rare (0.01% to 0.1%): Pyrexia

Frequency not reported: Malaise, increased LDH, elevated serum triglycerides, elevated serum cholesterol, rigors, substernal chest pain, ascites, changed temperature sensation, ear disorder (unspecified), enlarged abdomen, hot flashes, gangrene, influenza-like symptoms, leg pain, multiple organ failure, earache, abscess, herpes simplex, bacterial infection, viral infection, otitis media, sepsis, pain (including pain in back, chest, extremities), fatigue, face edema, flushing, aggravated condition

Postmarketing reports: Multi-organ failure

Nebulizer Solution:

-Very common (10% or more): Fatigue/asthenia (25%), decreased exercise tolerance, decreased weight

-Common (1% to 10%): Pyrexia

-Uncommon (0.1% to 1%): Increased blood alkaline phosphatase


Common (1% to 10%): Increased hepatic enzymes (ALT/AST, alkaline phosphatase, GGT)

Uncommon (0.1% to 1%): Abnormal hepatic function, increased blood bilirubin

Frequency not reported: Acute hepatocellular injury, cholecystitis, cholelithiasis, hepatic coma, hepatic necrosis, bilirubinemia, severe liver injury (including fatal cases with acute liver failure)

Postmarketing reports: Severe hepatotoxicity (including acute hepatitis and fatal events), hepatic failure (including fatal cases), hepatitis, jaundice

Nebulizer Solution:

-Common (1% to 10%): Increased ALT, increased AST

-Uncommon (0.1% to 1%): Hepatitis, hyperbilirubinemia, abnormal liver function test

Severe liver injury (including fatal cases with acute liver failure) has been reported, primarily in patients with severe underlying diseases.

A 74-year-old female developed hepatotoxicity and significantly increased AST (4962 units/L), ALT (7071 units/L), alkaline phosphatase (90 units/L), and total bilirubin (2.5 mg/dL) after starting this drug. Levels returned to normal within a week after discontinuation.

Severe hepatotoxicity usually occurred within 14 days (most within 6 days) after starting this drug and most cases were not associated with hypersensitivity. The majority of fatal hepatotoxicity cases occurred in patients 65 years or older and most were not associated with hypersensitivity.


Uncommon (0.1% to 1%): Allergic reaction

Rare (0.01% to 0.1%): Hypersensitivity

Postmarketing reports: Hypersensitivity reactions (sometimes fatal and including anaphylactic/anaphylactoid reactions, anaphylactic/anaphylactoid shock, serum sickness, angioneurotic edema)

Nebulizer Solution:

-Uncommon (0.1% to 1%): Hypersensitivity

Anaphylactic and anaphylactoid reactions have been reported, sometimes after the first dose.


Common (1% to 10%): Dyspnea

Uncommon (0.1% to 1%): Epistaxis

Frequency not reported: Rhinitis, sinusitis, pharyngitis, bronchitis, chronic obstructive airway disease, laryngitis, pleurisy, pneumonitis, upper respiratory tract infection, asthma, cough, hemoptysis, hiccough, hypoxia, pleural effusion, pulmonary embolism, respiratory insufficiency, airway obstruction, acute respiratory distress syndrome, aspiration, bronchospasm, emphysema, pneumonia, pneumothorax, pulmonary collapse, pulmonary edema, respiratory depression, respiratory disorder

Postmarketing reports: Allergic pneumonitis (isolated reports), dysphonia

Nebulizer Solution:

-Common (1% to 10%): Dysphonia, decreased pulmonary function test, abnormal breath sounds

-Uncommon (0.1% to 1%): Bronchospasm, bronchial hyper-reactivity, obstructive airways disorder


Uncommon (0.1% to 1%): Anemia, granulocytopenia, thrombocytopenia, eosinophilia, leukopenia

Rare (0.01% to 0.1%): Neutropenia

Frequency not reported: Decreased lymphocytes, abnormal WBCs (unspecified), abnormal platelets, agranulocytosis, hematoma, leukocytosis, lymphadenopathy, decreased prothrombin, purpura, thrombocythemia, serious hematological side effects (e.g., pancytopenia, agranulocytosis, hemolytic anemia)

Postmarketing reports: Hemolytic anemia, pancytopenia, aplastic anemia, prothrombin time prolonged, INR prolonged

Nebulizer Solution:

-Uncommon (0.1% to 1%): Anemia, neutropenia, increased eosinophil count, decreased platelet count

Serious hematological side effects (e.g., pancytopenia, agranulocytosis, hemolytic anemia) have been reported after systemic administration of this drug.


Frequency not reported: Renal calculi, allergic interstitial nephritis, increased nonprotein nitrogen

Postmarketing reports: Interstitial nephritis

Nebulizer Solution:

-Common (1% to 10%): Increased blood creatinine

-Uncommon (0.1% to 1%): Renal failure

A 73-year-old male developed vasculitis and acute renal failure within 3 days of starting oral therapy. Symptoms included significantly decreased urine output (0.5 to 0.7 L/day), palpable purpura, erythematous skin lesions, and increased serum creatinine (6.4 mg/dL) and BUN (190 mg/dL). The condition resolved within 4 weeks after discontinuation of this drug. Due to the possibility that this may have been an allergic reaction, rechallenge was not attempted.


Uncommon (0.1% to 1%): Anorexia, hyperglycemia, hyperkalemia, hypoglycemia

Frequency not reported: Decreased blood glucose, hypomagnesemia, thirst, aggravated diabetes mellitus, dehydration, hypokalemia, gout, hypernatremia, hypophosphatemia, weight decrease, fluid overload, hyponatremia, acidosis, symptomatic hypoglycemia, electrolyte abnormalities

Nebulizer Solution:

-Very common (10% or more): Anorexia

-Common (1% to 10%): Increased and decreased blood glucose


-Frequency not reported: Attacks of porphyria

Hypoglycemia has been reported, especially in diabetic patients.

A 79-year-old male with type 2 diabetes mellitus developed severe hypoglycemia (blood glucose 6 mg/dL) and became unresponsive 6 hours after receiving 1 dose of this drug (250 mg IV). Blood glucose levels subsequently ranged between 40 to 159 mg/dL with dextrose doses and infusions; however, he did not regain consciousness and expired 2 days later.

Attacks of porphyria in patients with porphyria have been associated with fluoroquinolone use.


Common (1% to 10%): Vaginitis

Uncommon (0.1% to 1%): Genital moniliasis

Frequency not reported: Dysmenorrhea, hematuria, dysuria, oliguria, urinary incontinence, urinary retention, leukorrhea, genital pruritus, ejaculation failure, impotence, albuminuria, candiduria, crystalluria, cylindruria, vaginal candidiasis, urinary tract infection

Nebulizer Solution:

-Common (1% to 10%): Vulvovaginal mycotic infection


Rare (0.01% to 0.1%): Visual disturbances (e.g., blurred vision)

Frequency not reported: Ophthalmologic abnormalities (including cataracts, multiple punctate lenticular opacities), abnormal vision, eye pain, nystagmus, conjunctivitis, transient vision loss

Postmarketing reports: Vision disturbance (including diplopia), reduced visual acuity, blurred vision, scotomata, uveitis

Nebulizer Solution:

-Uncommon (0.1% to 1%): Visual disturbance


Frequency not reported: Carcinoma


Common (1% to 10%): Injection site reactions (pain, reddening)

Frequency not reported: Injection site pain, injection site inflammation

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30. Lewis JR, Gums JG, Dickensheets DL “Levofloxacin-induced bilateral achilles tendonitis.” Ann Pharmacother 33 (1999): 792-5

32. Petitjeans F, Nadaud J, Perez JP, et al. “A case of rhabdomyolysis with fatal outcome after a treatment with levofloxacin.” Eur J Clin Pharmacol 59 (2003): 779-80

33. Briasoulis A, Agarwal V, Pierce WJ “QT Prolongation and Torsade de Pointes Induced by Fluoroquinolones: Infrequent Side Effects from Commonly Used Medications.” Cardiology 120 (2011): 103-110

35. Berger RE “Rates of torsades de pointes associated with ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin, and moxifloxacin.” J Urol 174 (2005): 165

36. Amankwa K, Krishnan SC, Tisdale JE “Torsades de pointes associated with fluoroquinolones: Importance of concomitant risk factors.” Clin Pharmacol Ther 75 (2004): 242-7

37. Frothingham R “Rates of torsades de pointes associated with ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin, and moxifloxacin.” Pharmacotherapy 21 (2001): 1468-72

39. Ramakrishnan K, Scheid DC “Diagnosis and management of acute pyelonephritis in adults.” Am Fam Physician 71 (2005): 933-42

40. Abo-Salem E, Nugent K, Chance W “Antibiotic-induced cardiac arrhythmia in elderly patients.” J Am Geriatr Soc 59 (2011): 1747-9

41. Samaha FF “QTC interval prolongation and polymorphic ventricular tachycardia in association with levofloxacin.” Am J Med 107 (1999): 528-9

45. Coban S, Ceydilek B, Ekiz F, Erden E, Soykan I “Levofloxacin-induced acute fulminant hepatic failure in a patient with chronic hepatitis B infection.” Ann Pharmacother 39 (2005): 1737-40

46. Karim A, Ahmed S, Rossoff LJ, Siddiqui RK, Steinberg HN “Possible levofloxacin-induced acute hepatocellular injury in a patient with chronic obstructive lung disease.” Clin Infect Dis 33 (2001): 2088-90

48. Solomon NM, Mokrzycki MH “Levofloxacin-induced allergic interstitial nephritis.” Clin Nephrol 54 (2000): 356

50. Famularo G, De Simone C “Nephrotoxicity and purpura associated with levofloxacin.” Ann Pharmacother 36 (2002): 1380-2

51. Singh N, Jacob JJ “Levofloxacin and hypoglycemia.” Clin Infect Dis 46 (2008): 1127

52. Laplante KL, Mersfelder TL, Ward KE, Quilliam BJ “Prevalence of and risk factors for dysglycemia in patients receiving gatifloxacin and levofloxacin in an outpatient setting.” Pharmacotherapy 28 (2008): 82-9

53. Lodise T, Graves J, Miller C, Mohr JF, Lomaestro B, Smith RP “Effects of gatifloxacin and levofloxacin on rates of hypoglycemia and hyperglycemia among elderly hospitalized patients.” Pharmacotherapy 27 (2007): 1498-505

54. Kelesidis T, Canseco E “Levofloxacin-induced hypoglycemia: a rare but life-threatening side effect of a widely used antibiotic.” Am J Med 122 (2009): e3-4

55. Graumlich JF, Habis S, Avelino RR, et al. “Hypoglycemia in inpatients after gatifloxacin or levofloxacin therapy: nested case-control study.” Pharmacotherapy 25 (2005): 1296-302

57. Micheli L, Sbrilli M, Nencini C “Severe hypoglycemia associated with levofloxacin in Type 2 diabetic patients receiving polytherapy: two case reports.” Int J Clin Pharmacol Ther 50 (2012): 302-6

58. Gibert AE, Porta FS “Hypoglycemia and levofloxacin: a case report.” Clin Infect Dis 46 (2008): 1126-7

59. Friedrich LV, Dougherty R “Fatal hypoglycemia associated with levofloxacin.” Pharmacotherapy 24 (2004): 1807-12

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

Related questions

  • Can Levaquin cause tendonitis?
  • What antibiotics are used to treat UTI?
  • What is the best antibiotic to treat a sinus infection?
  • What antibiotics are used to treat pneumonia?
  • Can you take Levaquin for an infected tooth?

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More about Levaquin (levofloxacin)

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levofloxacin (Rx)

Black Box Warnings

Serious adverse effects and limitations-of-use

  • Both oral and injectable fluoroquinolones are associated with disabling side effects involving tendons, muscles, joints, nerves and the central nervous system
  • Fluoroquinolones have been associated with disabling and potentially irreversible serious adverse reactions that have occurred together including: tendinitis and tendon rupture, peripheral neuropathy, and CNS effects
  • Discontinue the drug immediately and avoid use of systemic fluoroquinolones in patients who experience any of these serious adverse reactions
  • These side effects can occur hours to weeks after exposure to fluoroquinolones and may potentially be permanent

May exacerbate muscle weakness in patients with myasthenia gravis; fluoroquinolones should be avoided in patients with known history of myasthenia gravis

Because the risk of these serious side effects generally outweighs the benefits for patients with acute bacterial sinusitis, acute exacerbation of chronic bronchitis, and uncomplicated UTIs, that fluoroquinolones should be reserved for use in patients with these conditions who have no alternative treatment options

For some serious bacterial infections, including anthrax, plague, and bacterial pneumonia among others, the benefits of fluoroquinolones outweigh the risks and it is appropriate for them to remain available as a therapeutic option


Documented hypersensitivity


Anaphylactic reactions and allergic skin reactions, serious, occasionally fatal, may occur after first dose

Use caution in hematologic and renal toxicities

Hepatotoxicity reported with therapy

Peripheral neuropathy: Sensory or sensorimotor axonal polyneuropathy affecting small and/or large axons resulting in paresthesias, hypoesthesias, dysesthesias, and weakness reported; peripheral neuropathy may occur rapidly after initiating and may potentially become permanent

Commonly seen adverse reactions include tendinitis, tendon rupture, arthralgia, myalgia, peripheral neuropathy, and central nervous system effects (hallucinations, anxiety, depression, insomnia, severe headaches, and confusion); these reactions can occur within hours to weeks after starting therapy, including in patients of any age or without pre-existing risk factors; discontinue therapy immediately at first signs or symptoms of any serious adverse reaction; in addition, avoid use of fluoroquinolones, in patients who have experienced any serious adverse reactions associated with fluoroquinolones

Risk of developing fluoroquinolone-associated tendinitis and tendon rupture is increased in patients over 60 years of age, in patients taking corticosteroid drugs, and in patients with kidney, heart or lung transplants; other factors that may independently increase risk of tendon rupture include strenuous physical activity, renal failure, and previous tendon disorders such as rheumatoid arthritis (see Black Box Warnings)

Excessive sunlight may result in moderate-to-severe phototoxicity

Fatal hypoglycemia reported in elderly patients with or without diabetes; prompt treatment when symptoms are present is essential

May cause C difficile-associated colitis

Prolonged use may result in fungal or bacterial superinfection

Prolongation of QT interval and isolated cases of torsades de pointes; avoid use in patients with known QT prolongation, those with hypokalemia, and those taking other QT-prolonging drugs

May produce false-positive urine opiate screens

In prolonged therapy, perform periodic evaluations of organ system function (eg, renal, hepatic, hematopoietic); adjust dosage in renal impairment; superinfections may occur with prolonged or repeated antibiotic therapy

Pediatric patients may experience increased incidence of musculoskeletal disorders (eg, arthralgia, arthritis, tendinopathy, gait abnormality)

Clostridium difficile-associated diarrhea (CDAD) has been reported; if CDAD suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued; appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated

Prescribing antibiotics in absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to patient and increases risk of development of drug-resistant bacteria

CNS effects

  • Fluoroquinolones have been associated with an increased risk of CNS effects, including: convulsions, increased intracranial pressure (including pseudotumor cerebri), and toxic psychosis
  • May also cause CNS events including: nervousness, agitation, insomnia, anxiety, nightmares, paranoia, dizziness, confusion, tremors, hallucinations, depression, and psychotic reactions have progressed to suicidal ideations/thoughts and self-injurious behavior such as attempted or completed suicide; reactions may occur following the first dose; advise patients to inform their healthcare provider immediately if these reactions occur, discontinue treatment, and institute appropriate care
  • Fluoroquinolone are also known to trigger seizures or lower the seizure threshold; use with caution in epileptic patients and patients with known or suspected CNS disorders that may predispose to seizures or lower the seizure threshold (eg, severe cerebral arteriosclerosis, previous history of convulsion, reduced cerebral blood flow, altered brain structure, or stroke), or in the presence of other risk factors that may predispose to seizures or lower the seizure threshold (eg, certain drug therapy, renal dysfunction)

FDA MedWatch Safety Alert

  • Issued 12-20-2018
  • Increase in rate of aortic aneurysm and dissection reported within two months following use of fluoroquinolones, particularly in elderly patients
  • May occur with fluoroquinolones for systemic use (IV or PO)
  • Patients who have an aortic aneurysm or are at risk for an aortic aneurysm (eg, patients with peripheral atherosclerotic vascular diseases, hypertension, certain genetic conditions , elderly patients)
  • Prescribe fluoroquinolones to these patients only when no other treatment options are available
  • Advise patients to seek immediate medical treatment for any symptoms associated with aortic aneurysm
  • Stop treatment immediately if a patient reports side effects suggestive of aortic aneurysm or dissection
  • Issued July 10, 2018
  • The FDA is strengthening the current warnings in the prescribing information for fluoroquinolone antibiotics to inform clinicians of significant decreases in blood glucose and certain mental health adverse effects
  • Hypoglycemia, sometimes resulting in coma, occurred more frequently in elderly patients or in diabetic patients taking oral hypoglycemic medicine or insulin
  • Alert patients regarding hypoglycemic symptoms and carefully monitor blood glucose levels; instruct patients how to treat themselves if symptoms of hypoglycemia occur
  • This safety alert affects only systemic formulations; early signs and symptoms of low blood glucose include confusion, dizziness, feeling shaky, unusual hunger, headaches, irritability, pounding heart or very fast pulse, pale skin, sweating, trembling, weakness, and/or unusual anxiety
  • Mental health side effects are to be added to or updated across all the fluoroquinolones are disturbances in attention, disorientation, agitation, nervousness, memory impairment, and delirium
  • Inform patients of the potential risk of psychiatric adverse reactions that can occur after just 1 dose
  • Immediately discontinue treatment if CNS adverse effects occur, including psychiatric adverse reactions, or blood glucose disturbances occur and switch to a nonfluoroquinolone antibiotic if possible

About levofloxacin

Type of medicine A quinolone antibiotic
Used for Treating infections
Also called Tavanic®; Evoxil®
Available as Tablets

Levofloxacin is given to treat a bacterial infection. It is useful for treating infections such as sinusitis, chest infections, urine infections, prostatitis, and some skin and soft tissue infections. It works by killing the bacteria which are the cause of the infection.

Other antibiotics are usually prescribed in preference to levofloxacin. Levofloxacin is reserved for infections which have not improved with other antibiotic treatment. It is also used if other, more preferred, antibiotics cannot be prescribed for some reason.

Before taking levofloxacin

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking levofloxacin it is important that your doctor knows:

  • If you are pregnant, trying for a baby, or breastfeeding.
  • If you are under 18 years of age.
  • If you have ever experienced a problem with your tendons, called tendonitis.
  • If you have any problems with the way your kidneys work.
  • If you have epilepsy or any other condition that causes fits.
  • If you have ever had mental health problems.
  • If you have a heart condition, or if you have been told you have an unusual heartbeat.
  • If you have a condition causing tired and weak muscles, called myasthenia gravis.
  • If you know you have glucose 6-phosphate dehydrogenase (G6PD) deficiency. This is a genetic disorder which causes problems after eating foods such as fava beans.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
  • If you have ever had an allergic reaction to a medicine. It is particularly important that you tell your doctor if you have had a problem after taking another quinolone antibiotic (these are called norfloxacin, ofloxacin, ciprofloxacin, moxifloxacin, and nalidixic acid).

How to take levofloxacin

  • Before you start taking the tablets, read the manufacturer’s printed information leaflet from inside the pack. The manufacturer’s leaflet will give you more information about levofloxacin and a full list of the side-effects which you may experience from taking it.
  • Take levofloxacin exactly as your doctor tells you to. The usual dose is 500 mg daily, although for some types of infection a dose of 250 mg daily is sufficient, and for others, 500 mg twice daily is needed. Read the label carefully to make sure you know what dose is right for you.
  • You can take levofloxacin before or after meals. If you are taking one dose a day, it is preferable to take it in the morning. If you are taking more than one dose a day, try to space out your doses – so ideally, take a tablet every 12 hours.
  • Many people find it helps to swallow the tablets with a drink of water. You may break the tablets in half along the score line if needed, but do not crush or chew the tablets.
  • Do not take indigestion remedies (antacids) or medicines containing iron or zinc (such as multivitamin tablets) during the two hours before you take levofloxacin, or during the two hours after you have taken a dose. This is because these medicines interfere with the way levofloxacin is absorbed by your body, and stop it from working fully.
  • If you forget to take a dose, take it as soon as you remember. If when you remember, your next dose is due then take the dose which is due but leave out the forgotten one. Do not take two tablets together to make up for a missed dose.
  • Even if you feel your infection has cleared up, keep taking the antibiotic until the course is finished (unless you are told to stop by your doctor). This is to prevent the infection from coming back. A course of treatment usually lasts for 7-14 days. If you still feel unwell after finishing the course of tablets, go back to see your doctor.

Getting the most from your treatment

  • Remember to keep any routine appointments with your doctor. This is so your progress can be monitored.
  • Levofloxacin may cause your skin to become more sensitive to sunlight than normal. Protect your skin by using a sunscreen, particularly if you are exposed to strong sunlight for a prolonged period of time. Do not use sunbeds.
  • If you buy any medicines, check with a pharmacist that they are safe to take with this antibiotic. In particular, do not take painkillers called non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, while you are taking levofloxacin.
  • Some people develop thrush (redness and itching in the mouth or vagina) after taking a course of antibiotics. If you think you have thrush, speak with your doctor or pharmacist for advice.
  • This antibiotic may stop the oral typhoid vaccine from working. If you are having any vaccinations, make sure the person treating you knows that you are taking this medicine.
  • Levofloxacin may make you feel light-headed and impair your ability to concentrate. Make sure your reactions are normal before you drive and before use tools or machines.
  • If you have diabetes, you may need to check your blood sugar (glucose) levels more regularly, as levofloxacin can affect the levels of sugar in your blood.

Can levofloxacin cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with levofloxacin. You will find a full list in the manufacturer’s information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Common levofloxacin side-effects (these affect less than 1 in 10 people) What can I do if I experience this?
Feeling sick (nausea) or being sick (vomiting) Stick to simple foods – avoid rich or spicy meals. It may help to take the tablets after food
Diarrhoea Drink plenty of water to replace lost fluids. If the diarrhoea is severe or continues to be a problem, speak with your pharmacist or doctor for advice
Headache Drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If the headaches continue, let your doctor know
Feeling dizzy Do not drive and do not use tools or machines until you feel well again
Problems sleeping If troublesome, speak with your doctor
Temporary changes to liver enzymes This could be noticed if you have certain blood tests

Important: there are also a number of rare but more serious side-effects which have been associated with levofloxacin. Speak with your doctor as soon as possible if you experience the following:

  • An allergic-type reaction, such as swelling around your face or mouth, a skin rash, or any difficulty breathing.
  • Pain or inflammation in your muscles, tendons or joints (possible tendinopathy).
  • Any feelings of pain, burning, tingling, numbness or weakness.
  • Any problems with your vision or eyes, or changes to taste, smell or hearing.
  • Disordered thinking or thoughts about harming yourself.

If you experience any other symptoms which you think may be due to the tablets, speak with your doctor or pharmacist for advice.

How to store levofloxacin

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine, ask your pharmacist.

What is levofloxacin?

Levofloxacin a fluoroquinolone antibiotic that is prescribed to treat various infections caused by bacteria.

Levofloxacin is available as 250mg or 500mg tablets. It is also available infusion and nebuliser liquid, for severe infections.

Levofloxacin is also available as eye drops, with the brand name Oftaquix which are used to treat bacterial conjunctivitis.

Levofloxacin is only available on prescription in the UK.

What is levofloxacin used for?

Levofloxacin is an antibiotic medicine prescribed to treat various infections caused by bacteria. These include sinus infections (sinusitis), chest infections such as bronchitis and pneumonia, and skin infections.

Levofloxacin is also used to treat prostate infections (prostatitis) and urinary tract infections.

How does levofloxacin work?

Levofloxacin is a type of medicine called a quinolone antibiotic. It works by interfering with a bacterial enzyme involved in replicating and repairing the genetic material (DNA) of bacteria. If this enzyme doesn’t work, the bacteria cannot reproduce or repair themselves and this kills the bacteria and clears up the infection.

To make sure the bacteria causing an infection are susceptible to levofloxacin, your doctor may take a tissue sample, for example a swab from the throat or skin, or a urine or blood sample.

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Key facts about levofloxacin

▪️ Levofloxacin is not suitable for pregnant or breastfeeding women, children, teenagers or people with epilepsy.

▪️ Levofloxacin usually taken once or twice a day to treat infections.

▪️ Don’t take indigestion remedies or medicines containing iron or zinc in the two hours before or after taking a levofloxacin dose.

▪️ Avoid strong sunlight and don’t use sunbeds or sunlamps while you are taking levofloxacin.

▪️ The most common side effects of levofloxacin are diarrhoea, feeling or being sick, dizziness and headache.

▪️ It is ok to drink alcohol in moderation while taking levofloxacin.

▪️ People who have ever had problems with their tendons, such as tendonitis, caused by taking a quinolone-type antibiotic.

▪️ People who are allergic to other quinolone-type antibiotics, such as norfloxacin, ciprofloxacin, nalidixic acid should not take levofloxacin.

Levofloxacin should be used with caution by

  • People over 60 years of age.
  • People who are using corticosteroid medicines.
  • People with kidney problems.
  • People with a history or risk of having seizures (fits).
  • People with a history of psychiatric illness.
  • People suffering from myasthenia gravis.
  • People with diabetes (levofloxacin may affect your blood sugar levels).
  • People with G6PD deficiency (lack of an enzyme called G6PD in your blood).
  • People with heart disease, a very slow heartbeat, or an abnormal heart rhythm.
  • People with low levels of potassium or magnesium in your blood.

▪️ The levofloxacin dose prescribed and how long it needs to be taken for depends on the type of infection you have.

▪️ Levofloxacin tablets are usually taken once or twice a day, either with or without food.

▪️ Levofloxacin tablets should not be chewed or crushed, however if the tablets are scored they can be broken in half.

▪️ Don’t take antacids or medicines containing iron or zinc in the two hours before or after taking levofloxacin tablets.

▪️ Missed dose: If you forget to take a dose, take it as soon as you remember unless it’s nearly time for your next dose. In this case, leave out the missed dose and take your next dose as usual. Do not take a double dose to make up for a missed dose.

▪️ Finish the prescribed course, even if you feel better or it seems the infection has cleared up. Stopping the course early increases the chance that the infection will come back and that the bacteria will grow resistant to the antibiotic.

What are the side effects of levofloxacin?

Medicines and their possible side effects can affect people in different ways. The following are some of the side effects that may be associated with levofloxacin. Just because a side effect is stated here doesn’t mean that all people taking this antibiotic will experience that or any side effect.

Common side effects (affect between 1 in 10 and 1 in 100 people)

  • Feeling sick or vomiting.
  • Diarrhoea.
  • Headache.
  • Dizziness.
  • Difficulty sleeping (insomnia).

Uncommon side effects (affect between 1 in 100 and 1 in 1000 people)

  • Feeling sleepy. Don’t drive or operate machines if affected.
  • Thrush infections. Ask your pharmacist for advice if you think you’ve developed thrush, or any other new infection, while taking levofloxacin.
  • Stomach ache, indigestion or wind.
  • Feeling nervous, anxious or confused.
  • Skin rash or itching. Tell your doctor if you get a rash.

Rare side effects (affect between 1 in 1000 and 1 in 10,000 people)

Tell your doctor straight away if you get any of the following:

  • Changes to your vision such as blurred vision.
  • Tingling, burning or pins and needles sensations – a sign of nerve problems.
  • Pain or inflammation in your joints – a sign of tendon inflammation.
  • Diarrhoea that is severe, persistent or contains blood/mucus – a sign of bowel inflammation.
  • Fast heartbeat or palpitations.
  • Distressing thoughts or feelings, thoughts about harming yourself, hallucinations, mood changes or other unusual change in behaviour.
  • Skin rash, peeling or blistering.

Read the leaflet that comes with the medicine or talk to your doctor or pharmacist if you want any more information about the possible side effects of levofloxacin.

Read leaflet that is supplied with your medication for more information about side effects associated with levofloxacin. You can find a copy of this here

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If you think you have experienced side effects from levofloxacin you can report them using the yellow card scheme.

Can I take other medicines with levofloxacin?

Before you take levofloxacin, tell your doctor or pharmacist if you’re already taking any medicines, including those bought without a prescription and herbal medicines.

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Painkillers with levofloxacin

If you need a painkiller it is safe to take paracetamol or co-codamol with levofloxacin. Do not take anti-inflammatories (NSAIDs) like aspirin, ibuprofen, diclofenac or naproxen unless these have been prescribed by your doctor.

Contraceptive pills with levofloxacin

Levofloxacin doesn’t affect the contraceptive pill. However, if you experience vomiting or diarrhoea while taking this antibiotic, this can potentially make your pill less effective at preventing pregnancy. If this happens to you, follow the instructions for vomiting and diarrhoea described in the leaflet provided with your pills.

Anticoagulants with levofloxacin

Levofloxacin may enhance the anti-blood-clotting effect of anticoagulants such as warfarin, which may increase the risk of bleeding. If you’re taking warfarin your doctor may want to check your blood clotting time (INR) after you start and finish treatment with levofloxacin.

Medicines that reduce the absorption of levofloxacin

Don’t take any of the following in the two hours before or after taking a dose of levofloxacin; these medicines can reduce the absorption of levofloxacin from the gut and make it less effective:

  • antacids (for indigestion) containing aluminium or magnesium
  • medicines containing iron or zinc, including multivitamins
  • lanthanum
  • sucralfate (this is best taken at least two hours AFTER the levofloxacin)
  • Videx chewable/dispersible tablets (didanosine – these contain an antacid).

Other medicines interactions with levofloxacin

Make sure your doctor knows if you are taking any of the medicines listed below. Taking levofloxacin with these could potentially increase the risk of getting certain side effects, so your doctor may want to do some extra monitoring:

  • anti-inflammatory medicines such as diclofenac, naproxen, indomethacin.
  • benzydamine
  • celecoxib
  • mefenamic acid


The oral typhoid vaccine (Vivotif) should not be taken until at least three days after you have finished a course of this antibiotic, because the antibiotic could make this vaccine less effective.

Read more detailed information about medicines that may interact with levofloxacin here

Last updated 12.11.2019

Rita Ghelani (BPharm, MRPharmS) Pharmacist A UK registered practising pharmacist with over 20 years’ experience, Rita is a member of the medical journalists’ association (MJA) and has a wealth of experience in community pharmacy.

Common pill combos can put you at risk

Viewers of the medical drama “House” have come to expect bizarre explanations for every symptom: A sudden case of the sweats might be the work of a 20-foot tapeworm. Or a hidden brain tumor. Or a 20-foot tapeworm with a hidden brain tumor.

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If “House” mirrored real life, many episodes would center around a mundane culprit: a drug interaction. As Americans take more and more medications for everything from skittish stomachs to sluggish moods, clashes between drugs have fueled a new epidemic of unexpected, sometimes dangerous side effects and complications.

One recent study suggested that at least 1.3 million Americans have prescriptions for drugs that could cause problems if taken together — and that only counts people with health insurance. Although the overall toll is unknown, it’s undoubtedly huge, experts say … and growing.

Of course, if you take many medications at the same time, or large doses of a few, you’re more likely to run into a bad pairing, says Marietta Anthony, PhD, associate director of the Center for Education Research and Therapeutics at the University of Arizona. But even common items like drugstore pain relievers can clash with other meds. Scan our list: If you spot your prescription, be extra alert for signs of possible conflicts; then, talk to your doctor. And check our easy switches — you may be able to take a safer combo.

If you take…

An SSRI for depression

Selective serotonin reuptake inhibitors such as fluoxetine (Prozac), paroxetine (Paxil), or sertraline (Zoloft)

One possible conflict: A triptan drug used to treat migraines, such as sumatriptan (Imitrex), naratriptan (Amerge), or zolmitriptan (Zomig)

Why: Triptans and this type of antidepressant both increase levels of the brain chemical serotonin. But too much serotonin can set off a chemical firestorm known as serotonin syndrome, causing mania, an increased heart rate, seizures, and even death. The syndrome is rare, but the threat is real, says John Horn, PharmD, a professor of pharmacy at the University of Washington and coauthor of The Top 100 Drug Interactions. In 2006, the FDA issued an advisory to the roughly 50,000 Americans who take both SSRIs and triptans. The advisory told users they didn’t have to stop taking the drugs but cautioned them to be aware of the risk.

Protect yourself: Most patients can continue taking both triptans and SSRIs as long as they watch for signs of serotonin syndrome, Horn says. If you notice troubling symptoms, stop taking the triptans and check with your doctor right away.

Another possible conflict: Chronic use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin or ibuprofen.

Why: You may have heard that long-term use of NSAIDs can cause bleeding ulcers and other stomach troubles. What’s less widely known is that adding an SSRI increases the risk. Serotonin is the culprit here, too. Normally, that hormone encourages blood platelets to stick together —but because platelets soak up less serotonin when you’re on an SSRI, they may have trouble performing their number one job: clumping together to form clots and prevent excessive bleeding in the stomach and elsewhere.

Protect yourself: Even if you take an SSRI, it’s fine to pop a couple ibuprofen or aspirin for an occasional headache. But if you need several doses of a pain reliever each day — a common regimen for people with arthritis–take acetaminophen instead. It’s not an NSAID, and it doesn’t encourage bleeding.

If you take…

Blood pressure medication

Specifically ACE inhibitors, such as benazepril (Lotensin), or diuretics, such as furosemide (Lasix) or hydrochlorothiazide (HCTZ)

Possible conflict: Chronic use of NSAIDs, such as aspirin or ibuprofen

Why: If you take daily NSAIDs, your painkillers could keep these kinds of blood pressure medications from doing their job. These drugs work by ridding the body of extra salt or water, or by shutting off production of a hormone that prompts blood vessels to narrow. If taken regularly, NSAIDs can block both of these actions–and the blood pressure benefit.

Protect yourself: If you experience problems, you have two options (ask your doctor which is right for you). “You can switch to a different blood pressure medication,” Horn says: BP drugs called calcium channel blockers (such as amlodipine, or Norvasc) aren’t deterred by NSAIDs. Or swap the pain relievers–use acetaminophen instead.

If you take…

A quinolone antibiotic

Such as ciprofloxacin (Cipro), ofloxacin (Floxin), or levofloxacin (Levaquin) to treat a urinary tract infection, traveler’s diarrhea, or other problem

Possible conflict: Over-the-counter antacids containing calcium, magnesium, or aluminum, like Tums, Rolaids, Maalox, or Mylanta

Why: Quinolone antibiotics have an unhealthy attraction to the metals in common antacids. Magnesium, aluminum, and (to a lesser extent) calcium quickly glom on to the germ killers, rendering them much less effective. Protect yourself: You don’t have to put up with a sour stomach while you’re battling an infection. Simply wait an hour or two after taking your antibiotic before reaching for the antacid.

If you take…

Abnormal urine color can be distressing to patients. But did you know that discolored urine is usually harmless and is often due to medications? If your urine comes out as an odd color, don’t panic until you’ve reviewed this list.

Medications that can turn urine orange

  • Isoniazid, an antibiotic used for the treatment of tuberculosis
  • Sulfasalazine, an anti-inflammatory used to treat rheumatoid arthritis and ulcerative colitis
  • Riboflavin (also known as vitamin B2), a vitamin included in many over-the-counter multivitamins

Medications that can turn urine brown

  • Metronidazole (Flagyl), an antibiotic used to treat bacterial vaginosis, C. diff diarrhea and other gastrointestinal infections
  • Nitrofurantoin (Macrobid), an antibiotic used to treat and prevent urinary tract infections
  • Acetaminophen (Tylenol), when overdosed

Medications that can turn urine blue or green

  • Amitriptyline (Amitril), a medication used to treat depression
  • Cimetidine (Tagamet), an acid blocker used for GERD (acid reflux) and heartburn symptoms
  • Indomethacin (Indocin), an anti-inflammatory used for the treatment of gout
  • Zaleplon (Sonata), an atypical benzodiazepine used as a sleep medication
  • Methocarbamol (Robaxin), a non-sedating muscle relaxant used for neck and back pain
  • Metoclopramide (Reglan), a medication used to treat nausea

Medications that can turn urine red

  • Warfarin (Coumadin), a blood thinner used in patients who have blood clots in the leg (i.e. deep vein thrombosis or DVT), atrial fibrillation, or a heart valve replacement
  • Rifampin, an antibiotic used to treat tuberculosis and may be used as a second agent to treat folks with MRSA (methicillin-resistant staph aureus) infections
  • Phenazopyridine (Azo, Pyridium), an over-the-counter drug used to treat pain related to urinary tract infections
  • Ibuprofen (Advil, Motrin), a nonsteroidal anti-inflammatory pain reliever

– – –

Many of the causes of abnormal urine color are harmless effects of medications and foods. However, a change in urine color can be a sign of an underlying medical condition. If you stop your medication and your strange urine color still doesn’t go away, see your doc.

Dr O.

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