Antibiotics and sun exposure


10 types of medications that should keep you in the shade this summer

Drugs that magnify sunlight’s harmful effects require extra precautions.

Published: July, 2017

This time of year the outdoors beckons. Whether you’re relaxing on the deck, hiking on a trail, or basking on the beach, you’re probably well aware that exposure to the sun’s ultraviolet rays promotes wrinkles, skin cancer, and cataracts, and that its heat can make you susceptible to sunstroke. But you may not know that many medications can amplify the sun’s effects. “Some medications can make people more sensitive to the sun, especially if they have light skin or blue eyes,” says Dr. Laura Carr, a pharmacist at Harvard-affiliated Massachusetts General Hospital.

How drugs magnify the sun’s effects

Some drugs contain compounds that, when activated by the sun’s ultraviolet A (UVA) radiation, can damage cell membranes and, in some instances, DNA. The result can be a severe, blistering sunburn on the exposed parts of the body. Less frequently, drugs may trigger an allergic reaction to sun exposure, producing a rash that can cover the entire body.

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7 Medications That May Make You Extra Sensitive to Sun and Heat

This summer’s must-reads aren’t romances or thrillers; they’re the warning labels and package inserts for your drugs and supplements. As Consumer Reports on Health warned in a recent article, “ome widely used medications can make you far more sensitive to summer’s sunlight and heat than you’d usually be.”

That sensitivity can mean anything from a reduced ability to sweat to an increase in the amount of fluid you lose through your urine. So it’s important to revisit whatever safety info you have, and to check in with your doctor, who can let you know about potential risks during the brightest, warmest time of year, says Megan Rech, an emergency medicine clinical pharmacist at Loyola University Medical Center in Chicago.

“For the major players that interact with the sun and cause what’s called phototoxicity, those should be listed on the bottle or in the patient information,” explains Rech. “But there are a lot of medications that can cause interactions with the sun, so lesser-known side effects occur in fewer patients may not always be obvious.”

Here are some of the better-known substances that may allow summer’s sun and heat to hit you harder.

RELATED: Is It Risky to Drink While You’re On Medication? Depends on the Drug

Acne treatments

“Those can definitely be phototoxic, especially the retinoids,” says Rech. “Phototoxic effects are going to appear like a really bad sunburn.” The risk is more pronounced for prescription retinoids (such as Retin-A and Tazorac), which are significantly stronger than the products you’ll find at drugstores and beauty counters. But OTC acne and anti-aging products with retinol can cause dryness, peeling, and sun sensitivity as well. Products with salicylic acid and benzoyl peroxide can also increase your vulnerability. If you’re using one and plan to spend significant time outdoors, be sure to sport sunscreen and a broad-brimmed hat.


“Antibiotics can cause photosensitivity and phototoxic reactions, meaning that they’re going to worsen your sunburn,” Rech says. “The one that comes to mind right away is Bactrim, or sulfamethoxozole trimethoprim.” Bactrim is prescribed to treat everything from bronchitis to bladder infections. “That’s a big offender, and so are tetracyclines and fluoroqinolones.” That said, you should never, ever skip an antibiotic for the sake of sunbathing, warns Rech. Your doctor can help you juggle your plans and your meds.

Allergy medications

Some users find that oral antihistamines like diphenydramine (found in products like Benadryl and Dramamine) reduce their ability to sweat. In extreme cases, as the Consumer Reports medical advisory board noted, the overheating that can result leads to cramps, exhaustion, and even heat stroke. If you find that your allergy meds make it difficult for you to cool down, plan outdoor activities for the morning and evening, and try to spend the hottest hours of the day indoors.

RELATED: How to Tell If You’ve Spent Too Much Time Out in the Heat


Tricyclic antidepressants may cause problems in hot weather because they “prevent the area in your brain that regulates heat response from knowing you’re overheating,” Rech explains. “They can also decrease sweating, which leads to a decrease in heat loss.”

When you’re taking a drug that increases the likelihood of overheating, stay alert for warning signs such as headaches, lightheadedness, nausea, and weakness. If you experience any of those symptoms, get out of the sun and reach for water or a sports drink with sodium (which will help your body retain fluid until balance is restored). In the event of a severe reaction such as confusion, fever, or fainting, contact your doctor or call 911.

Non-steroidal anti-inflammatory drugs (NSAIDs)

“The main non-steroidals that cause phototoxicity are probably not ones that we commonly use,” Rech says. But still, caution should be used, especially if you’re on other medications. “Any time you’re taking a non-steroidal and going out in the sun I would recommend barrier protection with sunscreen and avoidance if possible, because any of the non-steroidals can worsen ,” Rech explains.

Vitamins and herbs

“A lot of over-the-counter herbal medications —for example, St. John’s Wort is a big inducer of photosensitivity, and that medication in particular has a number of drug interactions. Anyone should ask their doctor or pharmacist first,” says Rech. Another pill that might put you at risk: Niacin, a form of Vitamin B3 that’s used to treat high cholesterol. It can cause skin reactions, Rech says, “so it could potentially cause .”

RELATED: 6 Big Myths About Hydration

Topical medications

Significant sun exposure can amplify the effect of transdermal patches (such as Fentanyl, a powerful pain reliever, or Clonidine, which lowers blood pressure) that deliver medication directly through the skin. When you get a sunburn, the blood vessels in the surface of your skin dilate, explains Rech, and that can lead to increased absorption of your meds. So if you’re wearing a patch, it’s a good idea to consider long sleeves.

Physicians and pharmacists often advise patients to avoid prolonged exposure to sunlight while taking certain medications without telling them why. Those patients that do not heed this warning may later find a red itchy rash or sunburn in areas left unprotected from sunlight or the light emitted by tanning beds. As a clinical pharmacist, I have seen many patients who took tetracycline develop such a reaction. I myself discovered a sunburnlike reaction on my forehead whenafter taking doxycycline, a tetracycline derivative, for four daysI took a hatless 15-minute drive with the sunroof down.

Medications that react with the skin in this manner are termed photosensitizers. Examples include tetracycline and its derivatives, fluorquinolone antibiotics (such as Cipro), sulfa-containing drugs (such as Bactrim) and the cardiac medication amiodarone (which is sold under the brand name Cordarone). These photosensitizers, or chromophores, possess a unique ability to absorb ultraviolet light at the particular wavelength spectrum found in sunlight or artificial sunlight (UVA and UVB). This ability, however, is not the problem. Instead the unique structural characteristics of these medicationssuch as halogenated aromatic rings or alternating single and double bondslead to the destabilization of their chemical structure and a transfer of energy that induces a buildup of damaging compounds in the skin.

It is important to note that not all people will develop a reaction to a photosensitizer. Fair-skinned people may be more susceptible, much as they are to sun damage in general. The two distinct types of drug-associated photoreactions are phototoxic and photoallergic reactions. In the less common photoallergic reactions, the destabilized drug structure forms a complex called a hapten that prompts a localized immune response. White blood cells (lymphocytes and eosinophils) invade the skin and release immune mediators that cause increased leakage in the local veins, redness (erythema) and swelling (edema). In a few documented cases, even areas unexposed to the sun can become affected. Photoallergic reactions are usually delayed in onset and appear sometime after 24 hours of drug administration as a superficial dermatitislike reaction. These reactions may occur even after only one dose.

Phototoxic reactions, however, manifest as a more severe burn reaction and may arise within a few hours after the drug is taken. They usually involve a higher drug dosage than photoallergic reactions do. In these cases, destabilization of the drug structure results in an accumulation of free radicals and localized cell damage. This effect is more extensive than the superficial photoallergic reaction and leads to cell damage at multiple levels of the dermis and epidermis. People complain of a hot sensation in the affected area and often display redness. In some, this symptom progresses to blistering or peeling. With prolonged use of the drug, some people actually develop skin thickening and skin darkening or a loss of pigment in the area.

Treatment of photoallergic or phototoxic reactions should include stopping the drug and avoiding exposure to direct sunlight by wearing clothing and UVA/UVB blocking sunscreen for at least two weeks. Physical sunscreens such as those containing zinc or titanium oxide are preferred because chemical sunscreen may exacerbate the reaction. Cool, wet dressings may help soothe the irritated skin. Oral antihistamines such as diphenhydramine and topical corticosteroids such as hydrocortisone may also provide symptomatic relief. In extreme cases, corticosteroid therapy with prednisone, an oral tablet, may be required.

An important lesson is that every patient should ask their health care provider questions when they receive a prescription for a new drug. Review of the written information provided by your pharmacist or other health care provider should be a careful one. If further questions or concerns arise, you can always call your pharmacist or health care provider.

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Caution: Your Medications May Cause Severe Sunburn or Rashes

When the summer months arrive, most of us are eager to spend more time in the sun, but if you’re taking medication, some extra caution might be in order.

For reasons that aren’t entirely clear to researchers, a number of medications, in combination with the rays of the sun, can leave you with a severe rash or a blistering sunburn. Some drugs may even speed up the time it takes you to burn when you’re spending time outdoors. If the reaction is serious, you may need to start using a different medication or at least taking extra precautions to protect your skin from the sun.

“This time of year, sometimes people who have been taking the medication all year and have been fine will suddenly have a rash from it, because now they’re going out into the sun,” says Jennifer Stein, MD, PhD, a dermatologist at NYU Langone Medical Center in New York City.

A wide range of medications may have these sun-sensitive side effects, from antibiotics to common pain-relievers. Speak with your doctor and pharmacist to check if any of your medications can cause a worse sunburn — or even a skin rash in the sun.

Types of drugs that can make your skin more sun sensitive include these, among many others:

  • Antihistamine and sedative drugs, like Benadryl (diphenhydramine), and Phenergan (promethazine)
  • Common antibiotics like tetracycline, fluoroquinolones like Cipro, and sulfa-drugs like Bactrim (trimethoprim sulfamethoxazole)
  • Depression meds like Elavil (amitriptyline) and Sinequan (doxepin), for example
  • Diuretics, also called water pills, for example, Lasix (furosemide)
  • Heart-condition drugs, like the ACE-inhibitor Captopril, and arrhythmia drugs like Cordarone (amiodarone)
  • Pain relievers like Advil (ibuprofen) and the NSAID Aleve (naproxen)

Sunburn or Rash Could Be From Your Medication

Sun sensitivity to medications can appear as one of two different kinds of reactions, known as photoallergic and phototoxic reactions.

With photoallergic reactions, patients taking one of a number of medications, either orally or spread directly on the skin, will suddenly find themselves with an unexplained rash.

“Usually, we end up seeing those after the fact,” says Marie Leger, MD, PhD, a dermatologist at NYU Langone Medical Center.

She explains that with a topical medication, the rash will be found where you applied it. With an oral medication the rash typically appears on parts of your body with the highest level of sun exposure, such as your face, chest, and arms.

Phototoxic reactions, meanwhile, are more predictable. These medications are known to cause skin to react more quickly to sunlight.

“Even patients who don’t usually get sunburned, you have to caution them about it,” says Leger.

With proper precautions, patients on a medication with phototoxic side effects can typically continue on their medication. However, if you are taking a medication and have a photoallergic reaction, your will need to change medications.

As to the reason medications can have this side effect, “We don’t fully understand the mechanisms for it,” says Cheryl Rosen, MD, a professor at the University of Toronto and head of the division of dermatology at Toronto Western Hospital.

The current thinking is that either the drug, or a byproduct of the drug when it breaks down in the body, absorbs extra UV radiation from the sun’s rays, she explains

For the same reason, many people might not see a reaction, says Dr. Rosen, because they are not out in the sun as much, or aren’t out in the middle of day, or live further north.

At the same time, she says, you need to be aware of the risk of painful rashes or burns and wear sunscreen if you plan to be out — or even spend a day traveling in the car where some UV rays will get through the windows

If you are on medications with photosensitive side effects, be cautious:

  • Go out earlier or later in the day rather than at midday
  • Wear a hat
  • Wear sunscreen with a high SPF and broad-spectrum protection to block all types of UV rays

“Even if it’s rare, because the drugs are used a lot, going to be seen. So people on these drugs should be careful,” says Rosen, adding, “Everyone should be careful in the sun anyway.”

Drug-induced photosensitivity

What is drug-induced photosensitivity?

Drug-induced photosensitivity occurs when certain photosensitising medications cause unexpected sunburn or dermatitis (a dry, bumpy or blistering rash) on sun-exposed skin (face, neck, arms, backs of hands and often lower legs and feet). The rash may or may not be itchy.

Medications can also cause onycholysis (the nail plate lifting off the nailbed). This is known as photo-onycholysis.

Photo-onycholysis induced by doxycycline

What causes drug-induced photosensitivity?

Drug- and chemical-induced photosensitivity occurs when a drug or chemical agent combines with UV radiation to cause a phototoxic or photoallergic reaction. These agents are called photosensitisers and can be topical agents or medications that are taken orally. The following table lists the most common medications and topical agents causing photosensitivity.

Common photosensitising medications


  • Tetracyclines
  • Fluoroquinolones (eg, ciprofloxacin)
  • Sulfonamides

Nonsteroidal anti-inflammatory drugs (NSAIDs)

  • Ibuprofen
  • Naproxen
  • Ketoprofen
  • Celecoxib


  • Frusemide
  • Bumetanide
  • Hydrochlorothiazide


  • Isotretinoin
  • Acitretin


  • Sulfonylureas (eg, glipizide, glyburide)


  • Phenothiazines (eg, chlorpromazine, fluphenazine)
  • Thioxanthenes (eg, chlorprothixene)

Targeted therapies

  • Vemurafenib (50%)
  • Dabrafenib
  • Imatinib
  • Vandetanib

Other drugs

  • Amiodarone
  • Diltiazem
  • Quinine
  • Quinidine
  • Hydroxychloroquine
  • Enalapril
  • Dapsone
  • Voriconazole

The photosensitising properties of some drugs are sometimes used for therapeutic purposes in photodynamic therapy (PDT) and photochemotherapy (PUVA).

PDT photosensitisers

  • 5-aminolevulinic acid
  • Methyl-5-aminolevulinic acid
  • Porfimer sodium

PUVA photosensitisers

  • Methoxsalen (8-methoxypsoralen)
  • 5-methoxypsoralen
  • Trioxsalen

Common photosensitising topical agents


  • Benzophenones
  • Para-aminobenzoic acid (PABA)
  • Cinnamates
  • Salicylates


  • Musk
  • 6-methyl coumarin


  • 5-fluorouracil (oral and topical)
  • Coal tar

What are the clinical features of drug-induced photosensitivity?

The clinical features of drug-induced photosensitivity vary according to the photosensitising agent involved and the type of reaction it causes in the skin. The reaction can be phototoxic and/or photoallergic.

Phototoxic reactions result from direct damage to tissue caused by light activation of the photosensitising agent, whilst photoallergic reactions are a cell-mediated immune response in which the antigen is the light-activated photosensitising agent.

Photoallergic reactions occur less commonly than phototoxic reactions and are mostly caused by photosensitising topical agents. Although some oral photosensitising medications can cause photoallergic reactions, most cause phototoxic reactions. A handful of medications can cause both phototoxic and photoallergic reactions.

The clinical features differ between phototoxic and photoallergic reactions.

Phototoxic reactions

  • Skin reaction occurs minutes to hours after exposure to agent and light
  • Appears as an exaggerated sunburn reaction (reddening and swelling)
  • Vesicles, blisters and bullae may occur in severe reactions (pseudoporphyria)
  • May or may not be itchy
  • Less commonly, the skin may change colour, for example, a blue-green pigmentation is associated with amiodarone
  • The reaction is limited to sun-exposed skin
  • Photo-onycholysis (separation of the distal nail plate from the nail bed) may arise with many oral photosensitising medications and may be the only sign of phototoxicity in dark-skinned individuals

Photoallergic reactions

  • Eczematous, itchy type reaction occurs 24-72 hours after exposure to agent and light
  • May spread to areas that have not been sun-exposed
  • Hyperpigmentation does not occur

What is the treatment for drug-induced photosensitivity?

The main goal of treatment is to identify the photosensitising agent and if possible to avoid it. In cases where medication is being taken to treat an existing condition and cannot be discontinued, patients should be advised to follow strict sun protection strategies, including wearing sun protective clothing and using high protection-factor, broad-spectrum sunscreen.

If you’re making vacation plans to go somewhere warm and sunny this winter, it’s important to know beforehand that some of your medications could cause an unexpected problem. You may not be aware of this, but some prescription drugs can make you more sensitive to sunlight and cause your skin to burn more easily, a reaction known as photosensitivity.

What symptoms happen with photosensitivity?

If your medication has a warning to avoid sunlight or mentions photosensitivity as a possible side effect, don’t ignore it. Photosensitivity is an abnormally high sensitivity to ultraviolet (UV) rays from the sun.

This usually means that you could be more sensitive to sunlight and get sunburns more easily. It might not be a mild sunburn either. You may end up with a worse sunburn than usual—even a little exposure could mean a severe burn.

You could also become more sensitive to other light sources, including indoor fluorescent lights. The reaction to UV rays or fluorescent lights can cause itchy spots or areas of redness and swelling on patches of exposed skin.

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What medications can cause photosensitivity?

These common medications can make you more sensitive to the sun:

  • Antibiotics, particularly tetracyclines like doxycycline and fluoroquinolones like ciprofloxacin
  • Tricyclic antidepressants like amitriptyline and nortriptyline
  • Older antihistamines like promethazine
  • Griseofulvin, an antifungal medication
  • Quinine and other antimalarial medications
  • Acne medications like Accutane (isotretinoin) and Retin-A (tretinoin)
  • Some cancer drugs
  • Sulfonylurea drugs for diabetes like glyburide, glipizide, and glimepiride
  • Hydrochlorothiazide (HCTZ) and other thiazide diuretics
  • Some heart medications for arrhythmia, including amiodarone

How can I protect myself?

When you’re taking a medication that can cause you to be more sensitive to the sun, you’ll want to lower your risk for sunburns. First (and this may be obvious), avoid direct exposure to the sun. Stay away from tanning beds, too, as they can be even worse for you than direct sun exposure.

When you do spend time outside, wear sunscreen! Protective clothing like long sleeves, pants, hats, and sunglasses can also help.

And if you do get a sunburn, apply cool compresses, and drink water to make sure you don’t get dehydrated. You can’t speed up healing, but topical aloe vera gel can help relieve irritation, and ibuprofen can help minimize redness and inflammation.

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  • “People will take them and then go to the beach, and we’ll see them come in beet red with a head-to-toe sunburn,” Glatter says. “This is what’s called a phototoxic reaction.”

    “The majority of these drugs give you an exaggerated sunburn, but others might give you immediate burning,” says dermatologist Lorraine Young, cochief of dermatology clinical services and a clinical professor of medicine at the University of California, Los Angeles. “Your sunburn will be redder, more painful, more widespread—a worse sunburn, as if you were out in the sun longer than you actually were.”

    In addition to sunburns, some medications can cause allergic reactions—rashes, itching, blistering—to sunlight, sometimes several days after you were outside, says Kirby Lee, an associate professor of clinical pharmacology at the University of California, San Francisco.

    Many drugs also up your risk of heatstroke, a dangerous condition that requires immediate medical attention. They do this by reducing your body’s ability to sweat, increasing the amount that you urinate, and decreasing your thirst so that you’re less likely to drink an adequate amount of fluids, says Lee, who specializes in geriatrics and dementia. “Heatstroke symptoms can come on quite rapidly, especially in older adults, who often take more than one medication that raises their risk of overheating.”

    The following list is not comprehensive, but it does include the most common culprits. These drugs up your risk of sunburn, heatstroke or, in many cases, both:

    • Antibiotics, including tetracycline (Wesmycin), doxycycline (Vibramycin), fluoroquinolones (Cipro), levofloxacin (Levaquin) and sulfonamides (Bactrim, Septra)
    • Nonsteroidal anti-inflammatory drugs (NSAIDs), including ibuprofen (Advil and Motrin) and naproxen (Alleve)
    • Diuretics such as furosemide (Lasix), bumetanide (Bumex) and hydrochlorothiazide (HCTZ, Microzide)
    • Beta-blocker medications such as metoprolol (Lopressor, Toprol XL), atenolol (Tenormin), labetalol (Normodyne, Trandate) and carvedilol (Coreg)
    • Cardiac or blood pressure medications such as amiodarone (Cordarone) and quinidine; calcium channel blockers such as nifedipine (Procardia) and diltiazem (Cardizem); and ACE inhibitors such as enalapril
    • Tricyclic antidepressants, including amitriptyline (Elavil), nortriptyline (Pamelor), doxepin (Sinequan) and imipramine (Tofranil)
    • Antihistamines like diphenhydramine (Benadryl)
    • Anticholinergic drugs, such as Vesicare, that treat incontinence, overactive bladder and many other conditions
    • Antipsychotic drugs like haloperidol (Haldol), olanzapine (Zyprexa), quetiapine (Seroquel) and risperidone (Risperdal)
    • Stimulants such as methylphenidate (Ritalin) and dextroamphetamine (Adderall)
    • Decongestants such as pseudoephedrine and phenylephrine (Sudafed)
    • Diabetes drugs such as glyburide (DiaBeta)
    • Cancer chemotherapy drugs such as 5-fluorouracil (5-FU), vinblastine (Velban, Velsar) and dacarbazine (DTIC-Dome)
    • Supplements such as St.-John’s-wort and ginkgo

    Fortunately, you can reduce the risk of sun-sensitive side effects that accompany these drugs.

    Learn and label

    Review your current medications with your doctor or pharmacist to learn which, if any, put you at risk. Investigate alternative drugs at the same time. To easily keep track of which of your medications may cause problems, Glatter recommends that you mark each label with a sun symbol so that you see it every time you pick up the container.

    Consider substitutes

    You may be able to avoid or lower your risk of sun and heat complications by switching to a different medication. Instead of ibuprofen, for example, choose acetaminophen (Tylenol), Lee says. Benadryl can be replaced with Claritin or Zyrtec, though both should only be taken as needed and in the smallest effective dose. Check with your doctor before you switch to a new medication. Sometimes, though, you won’t have a choice, Lee says: “In such cases, you will need to change how you live within your environment.”

    Bactrim DS

    Generic Name: sulfamethoxazole and trimethoprim (SUL fa meth OX a zole and trye METH oh prim)
    Brand Name: Bactrim DS

    What is Bactrim DS?

    Bactrim DS (sulfamethoxazole and trimethoprim) is a combination antibiotic used to treat ear infections, urinary tract infections, bronchitis, traveler’s diarrhea, shigellosis, and Pneumocystis jiroveci pneumonia.

    Sulfamethoxazole and trimethoprim may also be used for purposes not listed in this medication guide.

    Important Information

    You should not use Bactrim DS if you have severe liver disease, kidney disease that is not being monitored, anemia caused by folic acid deficiency, if you take dofetilide, or if you have had low platelets caused by using trimethoprim or a sulfa drug.

    You should not take sulfamethoxazole and trimethoprim if you are pregnant or breastfeeding.

    Before taking this medicine

    You should not use this medicine if you are allergic to sulfamethoxazole or trimethoprim, or if you have:

    • severe liver disease;

    • kidney disease that is not being treated or monitored;

    • anemia (low red blood cells) caused by folic acid deficiency;

    • a history of low blood platelets after taking trimethoprim or any sulfa drug; or

    • if you take dofetilide (Tikosyn).

    Do not use if you are pregnant. Use effective birth control, and tell your doctor if you become pregnant.

    Do not breastfeed while using this medicine.

    This medicine should not be given to a child younger than 2 months old.

    Tell your doctor if you have ever had:

    • kidney or liver disease;

    • a folate (folic acid) deficiency;

    • asthma or severe allergies;

    • a thyroid disorder;

    • HIV or AIDS;

    • malnourishment;

    • alcoholism;

    • high levels of potassium in your blood;

    • porphyria, or glucose-6-phosphate dehydrogenase (G6PD) deficiency; or

    • if you use a blood thinner (such as warfarin) and you have routine “INR” or prothrombin time tests.

    How should I use Bactrim DS?

    Bactrim DS is taken by mouth.

    Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

    Drink plenty of fluids to prevent kidney stones while you are using this medicine.

    Sulfamethoxazole and trimethoprim doses are based on weight in children. Use only the recommended dose when giving this medicine to a child.

    Use this medicine for the full prescribed length of time, even if your symptoms quickly improve. Skipping doses can increase your risk of infection that is resistant to medication. This medicine will not treat a viral infection such as the flu or a common cold.

    You may need frequent medical tests.

    This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using sulfamethoxazole and trimethoprim.

    Store at room temperature away from moisture, heat, and light.

    What happens if I miss a dose?

    Use the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.

    What happens if I overdose?

    Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

    Overdose symptoms may include loss of appetite, vomiting, fever, blood in your urine, yellowing of your skin or eyes, confusion, or loss of consciousness.

    What should I avoid while using Bactrim DS?

    Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor before using anti-diarrhea medicine.

    Bactrim DS could make you sunburn more easily. Avoid sunlight or tanning beds. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

    Bactrim DS side effects

    Get emergency medical help if you have signs of an allergic reaction (hives, cough, shortness of breath, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

    Call your doctor at once if you have:

    • severe stomach pain, diarrhea that is watery or bloody (even if it occurs months after your last dose);

    • a skin rash, no matter how mild;

    • yellowing of your skin or eyes;

    • a seizure;

    • new or unusual joint pain;

    • increased or decreased urination;

    • swelling, bruising, or irritation around the IV needle;

    • increased thirst, dry mouth, fruity breath odor;

    • an electrolyte imbalance–headache, confusion, weakness, slurred speech, tingly feeling, chest pain, irregular heartbeats, loss of coordination or movement, feeling unsteady; or

    • low blood cell counts–fever, chills, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath.

    Common side effects may include:

    • nausea, vomiting, loss of appetite; or

    • mild itching or rash.

    This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

    What other drugs will affect Bactrim DS?

    You may need more frequent check- ups or medical tests if you also use medicine to treat depression, diabetes, seizures, or HIV.

    Many drugs can interact, and some drugs should not be used together. Tell your doctor about all your current medicines, especially:

    • amantadine, cyclosporine, indomethacin, leucovorin, methotrexate, pyrimethamine;

    • an “ACE inhibitor” heart or blood presure medication (benazepril, enalapril, lisinopril, quinapril, ramipril, and others); or

    • a diuretic or “water pill” (chlorthalidone, hydrochlorothiazide, and others).

    This list is not complete and many other drugs may affect Bactrim DS. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

    Where can I get more information?

    • Your pharmacist can provide more information about Bactrim DS (sulfamethoxazole and trimethoprim).
    • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
    • Every effort has been made to ensure that the information provided by Cerner Multum, Inc. (‘Multum’) is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum’s drug information does not endorse drugs, diagnose patients or recommend therapy. Multum’s drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

    Copyright 1996-2019 Cerner Multum, Inc. Version: 9.01.


    Before taking co-trimoxazole,

    • tell your doctor and pharmacist if you are allergic to co-trimoxazole, any other medications, or any ingredients in co-trimoxazole tablets and suspension. Ask your pharmacist for a list of ingredients.
    • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention the following: amantadine; angiotensin converting enzyme inhibitors such as benazepril (Lotensin), captopril (Capoten), enalapril (Vasotec), fosinopril (Monopril), lisinopril (Prinivil, Zestril), moexipril (Univasc), perindopril (Aceon), quinapril (Accupril), ramipril (Altace), and trandolapril (Mavik); anticoagulants (‘blood thinners’) such as warfarin (Coumadin, Jantoven); cyclosporine (Gengraf, Neoral, Sandimmune); oral diabetes medications such as glipizide (Glucotrol), glyburide (Diabeta, Glynase), metformin (Fortamet, Glucophage), pioglitazone (Actos), repaglinide (Prandin), rosiglitazone (Avandia); digoxin (Lanoxin); diuretics (‘water pills’); indomethacin (Indocin); leucovorin (Fusilev); medications for seizures such as phenytoin (Dilantin, Phenytek); memantine (Namenda); methotrexate (Trexall); pyrimethamine (Daraprim). and tricyclic antidepressants such as amitriptyline (Elavil), amoxapine (Asendin), desipramine (Norpramin), doxepin (Adapin, Sinequan), imipramine (Tofranil), nortriptyline (Aventyl, Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
    • tell your doctor if you have or have ever had thrombocytopenia (less than normal number of platelets) caused by taking sulfonamides or trimethoprim; megaloblastic anemia (abnormal red blood cells) caused by folate deficiency (low blood levels of folic acid), phenylketonuria (PKU, an inherited condition in which a special diet must be followed to prevent mental retardation), or liver or kidney disease. Your doctor may tell you not to take co-trimoxazole. Co-trimoxazole should not be used in children less than 2 months of age.
    • tell your doctor if you have or have ever had severe allergies; asthma; low levels of folic acid in the body which may be caused by malnutrition (you do not eat or cannot digest the nutrients needed for good health); human immunodeficiency virus (HIV) infection; porphyria (an inherited blood disease that may cause skin or nervous system problems); thyroid disease; or glucose-6-phosphate dehydrogenase (G-6-PD) deficiency (an inherited blood disease).
    • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking co-trimoxazole, call your doctor immediately. Co-trimoxazole can harm the fetus.
    • plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Co-trimoxazole may make your skin sensitive to sunlight.

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