Can bactrim make you tired

7 Shares By The Recovery Village Editor Camille Renzoni Reviewer Nathan Jakowski Updated on09/13/19

Mixing alcohol and Bactrim is not entirely safe. Alcohol can interact with many types of medication, including antibiotics like Bactrim. A general rule to follow is that if you are sick enough to require antibiotics, you should not be drinking alcohol. However, alcohol is a common part of social lives. Whether it’s a wedding, date, or birthday party, you may be interested in having a drink while on an antibiotic.

Bactrim is a commonly prescribed antibiotic used to treat bacterial infections including those in the ear, urinary tract, and respiratory system. You may know it by its generic name, sulfamethoxazole-trimethoprim, or SMZ-TMP.

While some antibiotics may be taken with moderate alcohol consumption, Bactrim is not one of them. Potentially harmful side effects can occur if you mix alcohol and Bactrim.

Side Effects of Mixing Alcohol and Bactrim

Your body relies on specific enzymes to break down alcohol into something that can be easily eliminated. Through this complex process, several byproducts are created. One of the byproducts is a toxic substance called acetaldehyde.

Bactrim may prevent the enzyme responsible for breaking down acetaldehyde from working, creating a buildup of the toxic substance. This interaction can lead to many side effects, including:

  • Flushing
  • Headaches
  • Nausea and vomiting
  • Difficulty breathing
  • Headache
  • Rapid heart rate

These effects may occur five to 15 minutes after consuming alcohol.

Key Points: Alcohol and Bactrim

There are several important points to remember about alcohol and Bactrim use.

  • Overall, it is not recommended to drink alcohol while taking antibiotics
  • The combination of Bactrim and alcohol specifically can cause serious side effects
  • If you require antibiotics and plan on drinking alcohol, be sure to tell your doctor
  • If you are finishing up a course of Bactrim, wait about a week before drinking alcohol

Have other questions about alcohol use? Check out these resources from The Recovery Village:

  • Alcohol-Related Topics
  • Commonly Asked Questions About Alcohol

Need help now for an alcohol abuse issue or addiction? The Recovery Village can help. We offer comprehensive treatment for alcohol addiction and our representatives are available to help you choose a program. Call today to learn more.

  1. Steckelberg, James M. “What are the effects of drinking alcohol while taking antibiotics?” The Mayo Clinic, 2018. Accessed March 22, 2019.
  2. Heelon, MW, White, M. “Disulfuram-cotrimoxazole reaction.” Pharmacotherapy, 1998. Accessed March 22, 2019
  3. “How long does it take Bactrim DS tablet to get out of your system?” Updated July 2018. Access March 2019.


Certain medications cause your skin to become more sensitive to the sun. Contrary to popular belief, they don’t make you more likely to burn, but actually cause a separate type of painful and itchy rash that can look like a bad burn. There are two types of photosensitive reactions: phototoxic and photoallergic.

Phototoxic is the most common. This happens when the drug itself gets dispersed throughout the body and ends up in the skin, where it absorbs UVA light and causes cellular damage. A phototoxic event typically happens within hours of initial exposure to sunlight.

Photoallergic reaction occur when the UV light alters the chemical structure of the drug and the body’s immune system sees this new compound as an intruder and attacks it. A photoallergic reaction doesn’t usually happen right away; it requires longer, and often multiple, exposures to sunlight before it happens.

Many commonly used medicines can cause photosensitivity:

Antibiotics such as ciprofloxacin (Cipro®), levofloxacin (Levaquin®), sulfamethoxazole/trimethoprim (Bactrim®) and doxycycline, tetracycline, and minocycline.

Acne medicines such as (isotretinoin (Accutane®/Claravis®), tazarotene (Tazorac®), and tretinoin)

Medicines to prevent malaria while traveling like atovaquone/proguanil (Malarone®) and chloroquine).

If you are taking a medication that can increase photosensitivity, you should avoid excessive exposure to sunlight and tanning beds. (Of course, you already know that you should avoid tanning beds anyway). If you don’t want to be a shut in while the sun shines, make sure you wear a broad spectrum (UVA/UVB) sunscreen with a SPF rating of 30 or greater. This will decrease that amount of sunlight exposure to your skin and therefore the risk of a bad reaction.

Sun Screen Tips:

  • Make sure it is broad spectrum (UVA & UVB)
  • Apply roughly one ounce of sunscreen for the full body
  • Apply one-half teaspoon of sunscreen to smaller body parts i.e. face/neck, each arm and shoulder
  • Apply one teaspoon of sunscreen to larger body parts i.e. legs, back
  • Apply 15-30 minutes prior to sunscreen exposure to ensure optimal protection
  • If swimming or being physically active use a “water resistant” sunscreen
  • Reapply liberally, especially if excessive swimming , sweating or toweling off
  • Minimally use a SPF of 15, optimally use a SPF of 30
  • If applying insect repellant, put the sunscreen on first, wait 15 minutes and then apply the insect repellant

If you are planning on spending a lot of time in the sun while on a medication, be sure to ask your pharmacist about possible photosensitivity side effects. The pharmacy staff at the Wilce Student Health Center is always willing to answer any questions you may have. Feel free to stop by or call us at (614) 292-0125.

Dean Wagner, PharmD candidate 2012
Student Health Services
The Ohio State University

Jason Goodman, PharmD, RPh
Student Health Services
The Ohio State University



Bactrim is the brand name of the generic antibiotic sulfamethoxazole trimethoprim (sometimes called co-trimoxazole).

The drug is a combination of two antibiotics: It’s one part trimethoprim (a synthetic drug), and five parts sulfamethoxazole (a sulfonamide drug).

Bactrim works against bacteria in the following types of infections:

  • Urinary tract infections (UTIs) caused by E. coli, Klebsiella, Enterobacter, Morganella morganii, Proteus mirabilis, and Proteus vulgaris
  • Middle-ear infections (acute otitis media) in children if they’re caused by the bacteria Streptococcus pneumoniae and Haemophilus influenzae
  • Chronic bronchitis when it worsens (acute exacerbations) and is caused by Streptococcus pneumoniae or Haemophilus influenzae
  • Some types of diarrhea, including dysentery, caused by Shigella flexneri and S. sonnei infections; and traveler’s diarrhea, caused by enterotoxigenic E. coli
  • Pneumonia caused by Pneumocystis jiroveci: for treatment, and sometimes for prevention when your immune system is compromised by immunosuppressant drugs or HIV/AIDS

Bactrim is also sometimes prescribed for other types of bacterial pneumonia, for acne, and for preventing urinary tract infections.

The Food and Drug Administration (FDA) first approved Bactrim in 1973. The drug is made by Mutual Pharmaceutical Co.

Bactrim Warnings

Bactrim shouldn’t be used by people who:

  • Are hypersensitive to trimethoprim or sulfonamide drugs (or have sulfa allergies)
  • Have suffered from thrombocytopenia (low blood platelet count) after taking trimethoprim or sulfonamides
  • Have megaloblastic anemia (low red blood cell count) caused by a folic acid deficiency
  • Are less than two months old
  • Have severe liver damage or poor kidney function that cannot be monitored

Though rare, the use of sulfonamides can cause severe and potentially fatal reactions, such as Stevens-Johnson syndrome.

Stop taking Bactrim and call your doctor right away if you develop a rash after taking Bactrim, and get emergency medical help if the rash starts to become severe or you feel like you are having an allergic reaction.

Other rare but serious reactions have included toxic epidermal necrolysis (a life-threatening skin condition), acute liver failure, agranulocytosis (severely low levels of white blood cells), aplastic anemia (when the body stops blood cell production), and other blood-related disorders.

As with most other antibiotics, Bactrim may cause prolonged diarrhea resulting from a difficult-to-treat Clostridium difficile (C. diff) infection.

Before taking Bactrim, also tell your doctor if you have:

  • Folic acid deficiency
  • Kidney or liver disease
  • Severe allergies
  • Bronchial asthma
  • An inherited blood disease called glucose-6-phosphate dehydrogenase (G-6-PD) deficiency
  • A thyroid disorder
  • Porphyria, an inherited enzyme disease that may cause skin and nervous system problems
  • Phenylketonuria, an inherited disorder that can cause intellectual disabilities if a strict diet is not maintained

Pregnancy and Bactrim

Bactrim may harm a developing fetus.

The drug has a warning that if you take it when you’re pregnant, it can cause such birth defects as urinary tract defects, cleft lip or palate, or club feet.

Before taking Bactrim, tell your doctor if you are pregnant or may become pregnant.

It should only be used during pregnancy if the benefits clearly outweigh the potential harms to the unborn child.

You should not breastfeed when taking Bactrim. The drug is excreted in breast milk and has the potential to harm breastfeeding infants, especially if they are ill, stressed, or premature.

Generic Name: sulfamethoxazole & trimethoprim
Product Name: Bactrim

Indication: What Bactrim is used for

Bactrim contains the active ingredients sulfamethoxazole and trimethoprim, also known as cotrimoxazole.

Bactrim is used to treat bacterial infections in different parts of the body.

Bactrim belongs to a group of medicines called antibiotics. There are many different types of medicines used to treat bacterial infections. Sulfamethoxazole in Bactrim belongs to a group of medicines known as sulfonamides. Trimethoprim belongs to a group of medicines known as the benzylpyrimidines.

Bactrim works by stopping the growth of the bacteria causing the infection.

Bactrim does not work against infections caused by viruses, such as colds and flu.

Bactrim has been prescribed for your current infection. Another infection later on may require a different medicine.

Your doctor may have prescribed Bactrim for another purpose.

Ask your doctor if you have any questions why Bactrim has been prescribed for you.

This medicine is available only with a doctor’s prescription.

Action: How Bactrim works

Bactrim works by stopping the growth of the bacteria causing the infection. It blocks two consecutive steps in the biosynthesis of nucleic acids and proteins essential to bacteria.

Bactrim does not work against infections caused by viruses, such as colds and flu.

Bactrim DS tablets and Bactrim oral suspension contain the active ingredients trimethoprim and sulfamethoxazole. Each Bactrim DS tablet contains 160 mg of trimethoprim and 800 mg of sulfamethoxazole and each 5 mL of Bactrim oral suspension contains 40 mg of trimethoprim and 200 mg of sulfamethoxazole. Bactrim DS tablets also contain inactive ingredients the povidone (1201), docusate sodium (480), sodium starch glycollate, magnesium stearate (470). Bactrim DS tablets are gluten free and lactose free. Bactrim oral suspension also contains the inactive ingredients cellulose – dispersible (460), methyl hydroxybenzoate (218), propyl hydroxybenzoate (216), sorbitol solution (420), polysorbate 80 (433), banana flavour 85509 H, vanilla flavour 73690-36, water. Bactrim oral suspension is gluten free and sugar free.

Dose advice: How to use Bactrim

Before you take Bactrim

When you must not take it

Do not take Bactrim if:

  • You have had an allergic reaction to sulfamethoxazole, trimethoprim, any other sulfonamide, or any of the ingredients listed here.
    • Some of the symptoms of an allergic reaction may include:
      • Skin rash;
      • Peeling of the skin;
      • Itching or hives;
      • Swelling of the face, lips or tongue which may cause difficulty in swallowing or breathing;
      • Wheezing or shortness of breath.
    • You have severe liver or kidney disease, any blood disorder or megaloblastic anaemia;
    • The child you are treating is less than 3 months of age;
    • You have streptococcal pharyngitis;
    • The package is torn or shows signs of tampering;
    • You are taking dofetilide, a medicine used to treat irregular heartbeats;
    • The expiry date (EXP) printed on the pack has passed.
      • If you take this medicine after the expiry date has passed, it may not work as well.

If you are not sure if you should be taking Bactrim, talk to your doctor.

Before you start to take it

Your doctor must know about all the following before you can start to take Bactrim.

Tell your doctor if:

  • You are pregnant or intend to become pregnant.
    • If Bactrim is taken late in pregnancy, it may harm the baby. Your doctor will discuss the risks and benefits of taking Bactrim during pregnancy.
  • You are breast-feeding or plan to breast-feed.
    • Bactrim passes into breast milk. Your doctor will discuss the risks and benefits of taking Bactrim while breast-feeding;
  • You have any other health problems including:
    • an allergic reaction to any diuretic (fluid) tablet or medicines for diabetes or overactive thyroid. This may increase your chances of an allergic reaction to Bactrim;
    • Any type of blood disorder (including porphyria and glucose-6-phosphate dehydrogenase deficiency);
    • Kidney or liver disease
    • A hereditary disorder called phenylketonuria;
    • Epilepsy (fits or convulsions);
    • Asthma;
    • Allergic disorders;
    • Rheumatoid arthritis;
    • Urinary obstruction;
    • Folic acid deficiency;
    • You are allergic to any other medicines, foods, dyes or preservatives.

Taking other medicines

Tell your doctor if you are taking any other medicines including any that you have bought from a pharmacy, supermarket or healthfood shop.

Some medicines may interfere with Bactrim. These medicines include:

  • Medicines used to treat diabetes such as repaglinide, rosiglitazone, pioglitazone, glibenclamide, gliclazide, glipizide, chlorpropamide and tolbutamide;
  • Fluid tablets (diuretics);
  • Phenytoin, a medicine for epilepsy;
  • Pyrimethamine, a medicine for malaria;
  • Other medicines used to treat infections such as rifampicin, dapsone and polymyxin;
  • Zidovudine, a medicine to treat HIV infection;
  • Cyclosporin, a medicine used to treat organ transplant patients;
  • Warfarin, acenocoumarol, phenprocoumon, medicines used to thin the blood;
  • Medicines used to treat certain heart conditions such as digoxin and amiodarone;
  • Amantadine, a medicine used to treat the influenza virus and Parkinson’s Disease;
  • Memantine, a medicine used to treat Parkinson’s disease;
  • Urinary acidifiers (for kidney conditions);
  • Oral contraceptives (“The Pill”);
  • Sulfinpyrazone, a medicine used to treat gout;
  • Salicylates, medicines to treat conditions such as psoriasis or warts;
  • Medicines used to treat cancer such as paclitaxel, mercaptopurine and methotrexate;
  • Clozapine, a medicine used to treat schizophrenia;
  • Medicines used to treat overactive thyroid conditions;
  • Medicines used to treat depression such as imipramine, clomipramine, amitriptyline, dothiepin, doxepin, nortriptyline and trimipramine;
  • Immunosuppressant medicines such as azathioprine and methotrexate;
  • Medicines used to treat high blood pressure as well as a variety of heart and kidney conditions such as captopril, enalapril, lisinopril, fosinopril, perindopril, quinapril, ramipril, trandolapril valsartan, telmisartan, irbesartan, candesartan, eprosartan, losartan, dofetilide and olmesartan.

These medicines may be affected by Bactrim or may affect how well it works. You may need to use different amounts of your medicine, or you may need to take different medicines. Your doctor will advise you.

Your doctor or pharmacist has more information on medicines to be careful with or avoid while taking Bactrim.

If you have not told your doctor about any of the above, tell them before you start taking Bactrim.

Use in very young children

Bactrim should not be given to premature babies or children younger than 3 months of age.

Use in people over 65 years

People over 65 years are more at risk of severe side effects when taking Bactrim. The risk is greater if you have kidney or liver disease or are taking some types of other medicines, such as diuretics.

Use in people with HIV infection

People with HIV infection have been reported to get more side effects while being treated with Bactrim than people without HIV.

How to take Bactrim

Follow all directions given to you by your doctor or pharmacist carefully.

They may differ from the information contained here.

How much to take

Take Bactrim exactly as your doctor has prescribed.

Your doctor will tell you how much Bactrim to take each day.

The dose and length of time you have to take Bactrim will depend on the type of infection you have.

For adults and children over 12 years, the usual dose of Bactrim DS is one tablet twice per day.

For children under 12 years of age, the dose of Bactrim oral suspension depends on the age and weight of your child. Your doctor or pharmacist will tell you how much your child should be given.

How to take it

Swallow Bactrim DS tablets whole (or halve them if necessary) with a glass of water.

The correct amount of Bactrim oral suspension should be measured, using a metric measure, before being given by mouth.

When to take it

Take Bactrim DS tablets or oral suspension after a meal.

How long to take Bactrim

Continue taking Bactrim until your doctor tells you to stop.

The full course of Bactrim prescribed by your doctor should be taken, even if you feel better after a few days. This will help clear your infection completely.

If your symptoms do not improve within a few days, or if they become worse, let your doctor know.

If you forget to take Bactrim

Do not take an extra dose. Wait until the next dose and take your normal dose then.

Do not try to make up for the dose that you missed by taking more than one dose at a time.

If you are not sure what to do, ask your doctor or pharmacist.

In case of an overdose

Immediately telephone your doctor or Poisons Information Centre (telephone 13 11 26) for advice or go to Accident and Emergency at your nearest hospital if you think that you or anyone else may have taken too much Bactrim even, if there are no signs of discomfort or poisoning.

You may need urgent medical attention.

If you take too much Bactrim, you may feel sick or vomit, feel dizzy, depressed or confused or have a headache. You may also feel drowsy or become unconscious.

Keep telephone numbers for these places handy.

If you are not sure what to do, contact your doctor or pharmacist.

While you are taking Bactrim

Things you must do

Tell all doctors, dentists and pharmacists who are treating you that you are taking Bactrim.

Tell your doctor if you become pregnant while taking Bactrim.

Tell your doctor if, for any reason, you have not taken your medicine exactly as prescribed.

Otherwise, your doctor may think that it was not effective and change your treatment unnecessarily.

Tell your doctor if you feel the tablets or oral suspension is not helping your condition.

Drink plenty of fluids while you are taking Bactrim.

This will help to flush the medicine through your system.

If you are taking Bactrim for a long time, visit your doctor regularly so your progress can be checked.

Your doctor may ask you to have regular tests to check your kidneys, liver or blood.

Tell your doctor you are taking Bactrim if you have to have any blood tests.

Bactrim may affect the results of some blood tests.

Contact your doctor immediately if you get severe diarrhoea, even if it develops several weeks after stopping Bactrim. Do not take any diarrhoea medicine without first checking with your doctor.

Diarrhoea medicines may make your diarrhoea worse or make it last longer.

Things you must not do

Do not stop taking Bactrim or change the dose without first checking with your doctor.

Do not let yourself run out of medicine over the weekend or on holidays.

Do not give Bactrim to anyone else even if their symptoms seem similar to yours.

Do not use Bactrim to treat other complaints unless your doctor says to.

Do not take any other medicines whether they require a prescription or not without first telling your doctor or consulting with a pharmacist.

Things to be careful of

Be careful driving or operating machinery until you know how Bactrim affects you.

Sometimes use of this medicine allows other bacteria and fungi which are not sensitive to Bactrim to grow. If other infections such as thrush occur while you are taking Bactrim, tell your doctor.

If you are going outdoors, wear protective clothing or use a SPF 15+ sunscreen.

Your skin may burn more easily while you are taking Bactrim.

After taking Bactrim


Keep your Bactrim DS tablets in the blister pack until it is time to take them.

Keep the oral suspension in the bottle until it is time to take it.

If you take the tablets out of the blister pack or the oral suspension out of the bottle before it is time to take them, they may not keep well.

Keep Bactrim in a cool dry place where the temperature stays below 30°C.

Do not store it, or any other medicine, in a bathroom or near a sink.

Do not leave it in the car or on window sills.

Heat and dampness can destroy some medicines.

Keep Bactrim where young children cannot reach it.

A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.


If your doctor tells you to stop taking Bactrim, or the tablets or oral suspension has passed its expiry date, ask your pharmacist what to do with any medicine that is left over.

Schedule of Bactrim

Bactrim is a Prescription Only (S4) medicine.

Side effects of Bactrim

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking Bactrim.

Bactrim helps most people with susceptible infections but it may have unwanted side effects in a few people.

All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical treatment if you get some of the side effects.

Ask your doctor or pharmacist to answer any questions you may have.

If side effects do occur, they may be:

  • Nausea, with or without vomiting;
  • Diarrhoea or other abdominal (gut) or stomach discomfort.

These side effects are not usually serious or long lasting.

Tell your doctor if you notice these side effects and they worry you:

  • Oral thrush (white, furry sore tongue and mouth);
  • Vaginal thrush (sore itchy vagina with vaginal discharge).

Your doctor will need to treat the thrush infection separately.

Tell your doctor immediately if you notice any of the following:

  • Jaundice (yellowing of the skin);
  • Severe or watery diarrhoea;
  • Any type of skin rash, peeling of the skin, severe itching or hives;
  • Fever, sore throat, lumps in the neck;
  • Cough, shortness of breath;
  • Severe persistent headache;
  • Discolouration of urine;
  • Swelling of the face and throat.

These symptoms are usually rare but may be serious and need urgent medical attention.

Very rarely, people have died from complications due to certain severe skin, liver or blood reactions. Elderly people, people with liver or kidney disease and people taking certain other medicines are more at risk of these severe reactions.

Other rare side effects include:

  • Other allergic reactions;
  • Pins and needles in the hands and feet;
  • Loss of appetite, fits, headaches, depression, imagined sensations or nervousness;
  • Increased or decreased urine production;
  • Unsteadiness or dizziness;
  • Sleeplessness, weakness, tiredness, increased sensitivity to light and stomach pains.

If you experience any of these effects contact your doctor as soon as possible.

This is not a complete list of all possible side effects. Others may occur in some people and there may be some side effects not yet known.

Tell your doctor if you notice anything else that is making you feel unwell, even if it is not on this list.

Ask your doctor or pharmacist if you don’t understand anything in this list.

Do not be alarmed by this list of possible side effects. You may not experience any of them.

For further information talk to your doctor.

This information from Lexicomp® explains what you need to know about this medication, including what it’s used for, how to take it, its side effects, and when to call your healthcare provider.

Brand Names: US

Bactrim; Bactrim DS; Sulfatrim Pediatric

Brand Names: Canada

APO-Sulfatrim; Protrin DF ; Septra; Sulfatrim; Sulfatrim DS; Sulfatrim Pediatric; TEVA-Trimel; TEVA-Trimel DS

What is this drug used for?

  • It is used to treat or prevent bacterial infections.

What do I need to tell my doctor BEFORE I take this drug?

For all patients taking this drug:

  • If you are allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
  • If you have anemia caused by a lack of folic acid.
  • If you have any of these health problems: Kidney disease or liver disease.
  • If you have any of these health problems: Asthma, porphyria, thyroid disease, not enough folate in the body, poor absorption, or poor nutrition.
  • If you have been drinking alcohol for a long time or are taking a drug for seizures.
  • If you have ever had a low platelet count when using trimethoprim or a sulfa (sulfonamide) drug.
  • If you are taking any of these drugs: Amantadine, cyclosporine, dofetilide, indomethacin, leucovorin, methotrexate, or pyrimethamine.
  • If you are taking or have recently taken any of these drugs: Benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, or trandolapril.
  • If you are taking a water pill.
  • If you are breast-feeding or plan to breast-feed.


  • If your child is younger than 2 months of age. Do not give this drug to an infant younger than 2 months of age.

This is not a list of all drugs or health problems that interact with this drug.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this drug with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take this drug?

All products:

  • Tell all of your health care providers that you take this drug. This includes your doctors, nurses, pharmacists, and dentists.
  • Have blood work checked as you have been told by the doctor. Talk with the doctor.
  • Have your urine checked as you have been told by your doctor.
  • This drug may affect certain lab tests. Tell all of your health care providers and lab workers that you take this drug.
  • Do not use longer than you have been told. A second infection may happen.
  • Be careful if you have G6PD deficiency. Anemia may happen.
  • If you have high blood sugar (diabetes), you will need to watch your blood sugar closely.
  • Talk with your doctor before you drink alcohol.
  • This drug may make you sunburn more easily. Use care if you will be in the sun. Tell your doctor if you sunburn easily while taking this drug.
  • Rarely, very bad effects have happened with sulfa drugs. Sometimes, these have been deadly. These effects have included liver problems, blood problems, and very bad skin reactions (Stevens-Johnson syndrome/toxic epidermal necrolysis). Call your doctor right away if you have a rash; red, swollen, blistered, or peeling skin; red or irritated eyes; sores in your mouth, throat, nose, or eyes; fever, chills, or sore throat; cough that is new or worse; feeling very tired or weak; any bruising or bleeding; or signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
  • This drug may raise the chance of a very bad brain problem called aseptic meningitis. Call your doctor right away if you have a headache, fever, chills, very upset stomach or throwing up, stiff neck, rash, bright lights bother your eyes, feeling sleepy, or feeling confused.
  • If you are 65 or older, use this drug with care. You could have more side effects.
  • This drug may cause harm to the unborn baby if you take it while you are pregnant. If you are pregnant or you get pregnant while taking this drug, call your doctor right away.


  • If you are allergic to sulfites, talk with your doctor. Some products have sulfites.
  • This drug has propylene glycol in it. Too much propylene glycol may lead to very bad health problems like nervous system problems, kidney problems, or other organ problems. If you have questions, talk with the doctor.
  • Some products have benzyl alcohol. Do not give a product that has benzyl alcohol in it to a newborn or infant. Talk with the doctor to see if this product has benzyl alcohol in it.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

All products:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of a high potassium level like a heartbeat that does not feel normal; change in thinking clearly and with logic; feeling weak, lightheaded, or dizzy; feel like passing out; numbness or tingling; or shortness of breath.
  • Signs of low blood sugar like dizziness, headache, feeling sleepy, feeling weak, shaking, a fast heartbeat, confusion, hunger, or sweating.
  • Signs of kidney problems like unable to pass urine, change in how much urine is passed, blood in the urine, or a big weight gain.
  • Signs of low sodium levels like headache, trouble focusing, memory problems, feeling confused, weakness, seizures, or change in balance.
  • Muscle or joint pain.
  • Purple patches on the skin or mouth.
  • Shortness of breath.
  • Hallucinations (seeing or hearing things that are not there).
  • Mood changes.
  • Diarrhea is common with antibiotics. Rarely, a severe form called C diff–associated diarrhea (CDAD) may happen. Sometimes, this has led to a deadly bowel problem (colitis). CDAD may happen during or a few months after taking antibiotics. Call your doctor right away if you have stomach pain, cramps, or very loose, watery, or bloody stools. Check with your doctor before treating diarrhea.


  • This drug may irritate the vein. If the drug leaks from the vein, it may also cause irritation around that area. Tell your nurse if you have any redness, burning, pain, swelling, or leaking of fluid where the drug is going into your body.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Upset stomach or throwing up.
  • Diarrhea.
  • Not hungry.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to your national health agency.

How is this drug best taken?

Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.

All oral products:

  • Take with or without food. Take with food if it causes an upset stomach.
  • Take with a full glass of water.
  • Take this drug at the same time of day.
  • Keep taking this drug as you have been told by your doctor or other health care provider, even if you feel well.
  • Drink lots of noncaffeine liquids unless told to drink less liquid by your doctor.

Liquid (suspension):

  • Shake well before use.
  • Measure liquid doses carefully. Use the measuring device that comes with this drug. If there is none, ask the pharmacist for a device to measure this drug.


  • It is given as an infusion into a vein over a period of time.
  • Drink lots of noncaffeine liquids unless told to drink less liquid by your doctor.

What do I do if I miss a dose?

All oral products:

  • Take a missed dose as soon as you think about it.
  • If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
  • Do not take 2 doses at the same time or extra doses.


  • Call your doctor to find out what to do.

How do I store and/or throw out this drug?

All oral products:

  • Store at room temperature protected from light. Store in a dry place. Do not store in a bathroom.


  • If you need to store this drug at home, talk with your doctor, nurse, or pharmacist about how to store it.

All products:

  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

General drug facts

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else’s drugs.
  • Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Consumer Information Use and Disclaimer

This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Last Reviewed Date


10 Side Effects of Antibiotics–and What to Do About Them

If diarrhea becomes severe, it could be a more serious condition called clostridium difficile-associated diarrhea. “This happens when the antibiotic has killed the good bacteria in the gut and the bad bacteria has overgrown,” says Dzintars. This condition can cause dehydration and may require hospitalization, so call your doctor if you’re experiencing watery diarrhea several times a day.

Antibiotics can also cause an overgrowth of bacteria in the small intestine, which can contribute to bloating and cramping that continues even after you’ve stopped taking them. This type of infection usually requires more (but different) antibiotics to bring the gut’s bacterial balance back to normal.


Headaches are another common complaint from people taking antibiotics. “If you have a headache and you don’t think it’s from sleep deprivation or caffeine deprivation, it certainly could be the antibiotic you’re taking,” says Dzintars.

“Usually these headaches aren’t severe, and they’re only temporary,” she adds. “And as long as it’s not causing excruciating pain, an over-the-counter analgesic can usually help.”

RELATED: The 14 Kinds of Headaches

Sensitivity to sun

Certain antibiotics are photosensitizers, which means they affect how the skin reacts to ultraviolet light. Exposure to sunlight while on these drugs can increase the risk of sunburn, blistering, peeling, and subsequent damage to skin cells. Some of these drugs can also interact with sunlight to cause a red, itchy rash—even in just as little as 15 minutes of exposure, according to Scientific American.

That’s why people taking drugs such as tetracyclines, fluoroquinolones, and sulfa drugs should avoid prolonged periods of sun exposure, especially between the hours of 10 a.m. and 2 p.m., and should wear broad-spectrum sunscreen and protective clothing if they do spend time outside. Some common examples of those drugs include doxycycline, Cipro, and Bactrim.

Drug interactions

Taking antibiotics may treat your bacterial infection, but it could also cause other medications you’re currently on to work differently—or not as well. Drugs that can interact with antibiotics include blood thinners, antacids, antihistamines, anti-inflammatory drugs (like over-the-counter pain medicines), psoriasis medications, diuretics, antifungal drugs, steroids, diabetes medications, muscle relaxants, migraine medications, and some antidepressants.

Hormonal birth control can also be less effective when taken with the antibiotic rifampin—but fortunately, that drug is rarely prescribed; most common antibiotics haven’t been shown to affect contraceptive failure rates. Keep in mind, however, that if an antibiotic causes vomiting, there’s a chance your body may not absorb your daily birth control pill as it should.

Antibiotics can also interact with alcohol. Specifically, the drugs metronidazole, tinidazole, and trimethoprim sulfamethoxazole “should never be mixed with any amount of alcohol, because the combo can cause an unpleasant reaction which may include headache, flushing, a rapid heartbeat, nausea, and vomiting,” according to Health’s medical editor Roshini Rajapaksa, MD.

Having one or two drinks while on other types of antibiotics isn’t as big a deal, says Dr. Raj, although some people find that the drugs’ common side effects (like upset stomach or dizziness) are enhanced by alcohol. If you’re sick and already taking antibiotics, remember that it’s not just booze you should watch out for: Some cold medicines contain alcohol, as well.

RELATED: Warning: Do Not Mix These Supplements

Fungal infections

Because antibiotics alter the bacterial makeup in our bodies, they can leave us vulnerable to yeast infections and other types of fungal growth, says Dzintars. These infections can happen in the mouth (known as oral thrush), on the skin, or under fingernails or toenails, to name a few common spots.

Antibiotics—especially if they’re taken long-term—can also upset the bacterial balance found in a woman’s vagina. This can change her pH and can contribute to yeast infections down there, as well. Taking an anti-yeast medication (like Monistat) while you’re on antibiotics may help prevent this side effect, but check with your doctor before you add another drug to your regimen.

That recent case of black hairy tongue may also be related to fungus. Antibiotics—particularly tetracyclines—can cause the tiny bumps on the tongue’s surface (called papillae) to grow longer and trap more bacteria, tobacco, food, and, yes, yeast, which can all cause discoloration and a furry appearance. Fortunately, when antibiotics are to blame, the condition usually goes away soon after the drugs are stopped.

RELATED: 8 Gross Infections You Can Catch at the Gym–and How to Avoid Them


Some of the scariest—and most dangerous—side effects of antibiotics involve allergic reactions. In fact, says Dzintars, allergic reactions to antibiotics are one of the most common reasons people go to hospital emergency departments.

“People may break out into rashes or hives, have swelling in their lips, or become short of breath,” says Dzintars. They can even have a full-on anaphylactic reaction, in which their throat swells shut and they need a dose of epinephrine right away to save their life.

These reactions aren’t common, but they’re definitely something to watch out for if you’re prescribed a new drug you haven’t used before. Being allergic to one type of antibiotic doesn’t preclude you from using other types, says Dzintars, but it does mean you’ll have to be careful not to use anything else in the same family.

RELATED: 12 Signs You Are Having an Allergic Reaction

Tooth staining

Some research suggests that tetracycline antibiotics can cause permanent staining or discoloration of children’s permanent teeth. As a result, since 1970, all drugs in this class have been prescribed with a warning label that advises against their use in children under 8. (Taking these drugs during pregnancy has also been linked to stained teeth in a woman’s offspring.)

But the Centers for Disease Control and Prevention (CDC) points out that doxycycline, a newer tetracycline-class antibiotic, “binds less readily to calcium and has not been shown to cause the same tooth staining.”

That’s important, since doxycycline is the best treatment for Rocky Mountain Spotted Fever, a potentially deadly tickborne disease. Misperceptions about this drug—and doctors’ fears of staining their patients teeth—may prevent kids from getting lifesaving treatment, the CDC says.


Drugs known as fluoroquinolones (including Cipro and Levaquin) used to be a popular choice for treating common conditions like pneumonia, bronchitis, and urinary tract infections. But in recent years, doctors have realized that these drugs tend to cause more—and more serious—side effects than other classes of antibiotics.

Some of those side effects involve damage to the tendons that connect muscle to bone, including reports of pain (tendonitis), injury (tendinopathy), or even rupturing. The FDA has added warnings to these drugs’ packaging about the risk of tendonitis as well as permanent nerve damage. In 2016, the agency advised that fluoroquinolones should only be used as a last resort drug.

Seeing double

A 2009 study published in Ophthalmology suggested that fluoroquinolone use was also associated with double vision, also known as diplopia. Researchers found 171 cases of double vision among fluoroquinolone users between 1986 and 2009, with an average time of 9.6 days between the start of medication and the onset of symptoms.

Because this type of antibiotic has also been linked to tendonitis, the authors theorized that pain and stiffness in the muscles around the eye may be to blame for this additional side effect, as well. They also say that thorough vision and neurological exams should be done for patients exhibiting this symptom, in order to rule out other causes.

RELATED: 11 Reasons Your Vision Is Blurry–and What to Do About It

Depression and anxiety

Fluoroquinolones, along with penicillin and other drugs in its family, have also been linked to depression and anxiety. In one 2015 study in the Journal of Clinical Psychiatry, the more courses of antibiotics a person had over their lifetime, the more likely they were to have depression and anxiety.

Antibiotics change the makeup of the body’s microbiome, the researchers suggest, which may affect neurologic pathways, metabolism, and immunity—all of which could have effects on a person’s mental health.

These are just some of the reasons antibiotics should only be taken as needed, and only as directed by a doctor, says Dzintars. (The growing threat of antibiotic-resistant bacteria—which is fueled in part by overprescription of the drugs—is yet another.)

“A lot of people assume that antibiotics are safe and that they’re going to be a magic bullet for whatever’s wrong,” says Dzintars. “And yes, they are our best defense against bacteria that have been here a lot longer than we have—but we need to treat with the right drug, with the right dose, for the right duration, and we need to be aware of their risks, as well.”

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