Prescription onlyLower-cost generic available


(Sulfamethoxazole / Trimethoprim)

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Kills bacteria.

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Prescription onlyLower-cost generic available

Our bottom line

Bactrim (Sulfamethoxazole / Trimethoprim) is good for treating many bacterial infections and is available as a generic. However, you can be more likely to sunburn. Also, it can cause birth defects, so talk to your doctor if you're pregnant.


  • Available in generic.
  • Available in different forms: tablet, capsule and suspension.
  • Used to treat many types of bacterial infections.
  • Less resistance seen to this antibiotic. Your doctor may run tests to see if Bactrim responds to your infection.
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  • Makes your skin more sensitive to the sun.
  • Has to be taken with plenty of liquids.
  • May cause birth defects.
  • Can cause diarrhea.

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What to expect when you take Bactrim (Sulfamethoxazole / Trimethoprim)

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Tips from our pharmacists
  • Take this medication exactly how your doctor tells you to.
  • Can make your skin more sensitive to the sun.
  • Drink plenty of liquids when taking the medication.
  • Can cause diarrhea, nausea or vomiting.
  • Can cause rash.
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Side effects for Bactrim (Sulfamethoxazole / Trimethoprim)

Manufacturers don’t say how common these side effects are

  • Abdominal pain
  • Agranulocytosis
  • Allergic myocarditis
  • Anorexia.
  • Aplastic anemia
  • Aseptic meningitis
  • Bleeding disorder
  • Blood disorder
  • Blood vessel disease
  • Body shaking
  • Bun and serum creatinine elevation
  • Chills
  • Cholestatic jaundice
  • Conjunctival and scleral injection
  • Cough
  • Crystalluria and nephrotoxicity in association with cyclosporine
  • Decreased liver function
  • Deep skin swelling
  • Destruction of red blood cells
  • Diarrhea
  • Drug fever
  • Eosinophilia
  • Erythema multiforme
  • Exfoliative dermatitis
  • Fatigue
  • Generalized allergic reactions
  • Generalized skin eruptions
  • Hallucinations
  • Headache
  • Henoch-schoenlein purpura
  • Hives
  • Hyperkalemia
  • Interstitial nephritis
  • Itching
  • Joint pain
  • Kidney failure
  • Lack of interest or enthusiasm
  • Lack of muscle coordination
  • Large blood cell anemia
  • Liver inflammation
  • Low blood sodium
  • Low mood disorder
  • Low white blood cells
  • Low white blood cells
  • Lupus, autoimmune disorder
  • Mouth and lip swelling
  • Muscle pain
  • Nausea
  • Nausea
  • Nerve damage
  • Nervousness
  • Pancreatitis
  • Pseudomembranous enterocolitis
  • Pulmonary infiltrates
  • Rash
  • Rhabdomyolysis
  • Ringing in the ears
  • Sensitivity to light
  • Serious allergic reaction
  • Serum sickness-like syndrome
  • Shortness of breath
  • Sleep difficulty
  • Stevens-johnson syndrome
  • Sudden liver failure
  • Thrombocytopenia
  • Tongue inflammation
  • Toxic epidermal necrolysis
  • Toxic nephrosis with oliguria and anuria
  • Vertigo
  • Vomiting
  • Vomiting
  • Weakness

Risks and Warnings for Bactrim (Sulfamethoxazole / Trimethoprim)

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  • As with all antibiotics, Bactrim (Sulfamethoxazole / Trimethoprim) can cause diarrhea. If this happens while you're taking the medication, taking probiotics in the form of yogurt, supplements or drinks a few hours after you take the medication may help. If you develop an unusual diarrhea with loose or bloody stools weeks after you finish the medication, talk to your doctor as this can be a rare but serious side effect.

Means that some groups have a high risk of experiencing this side effect

Tips from pharmacists and people taking Bactrim (Sulfamethoxazole / Trimethoprim)

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The FDA category for this medication is D. It is advised that you: Weigh risks vs. benefits