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Bactrim

Generic Name: Sulfamethoxazole-trimethoprim

Side Effects & Precautions

Medically reviewed by Jessica Swirble, PharmD
Last updated on 3/27/2024

Drug Information | Side Effects | Use & Dosage | Request a Prescription

What are the side effects of Bactrim (sulfamethoxazole-trimethoprim)?

The use of Bactrim has been shown to cause side effects in some patients.

Common mild side effects of Bactrim use include:

  • Nausea
  • Vomiting
  • Diarrhea
  • Loss of appetite
  • Skin rash
  • Itching
  • Headache
  • Dizziness
  • Fatigue/ tiredness

More severe side effects include:

  • Severe skin reactions
  • Severe stomach pain
  • Joint pain
  • Liver damage or jaundice
  • Blood disorders
  • Irregular heartbeat
  • Kidney problems (such as acute kidney injury)
  • Severe allergic reactions (such as swelling, difficulty breathing, hives)

Seek medical attention immediately if you experience any severe symptoms while taking Bactrim. If you experience mild side effects that become severe or do not go away after a few days, speak to a healthcare provider right away.

What should I tell my healthcare provider before using Bactrim (sulfamethoxazole-trimethoprim)?

Before starting treatment with Bactrim, tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with this drug.

Tell your provider if you are taking these medications or supplements:

  • ACE inhibitors (e.g., benazepril, captopril, enalapril)
  • Angiotensin receptor blockers (e.g., losartan, valsartan)
  • Diuretics ('water pills')
  • Methotrexate
  • Warfarin
  • Phenytoin
  • Digoxin
  • Cyclosporine
  • Sulfonylureas (e.g., glipizide, glyburide)
  • Cannabis

You should also mention medical conditions such as:

  • Kidney disease
  • Liver disease
  • Blood disorders
  • Allergies to sulfa drugs or trimethoprim
  • Asthma or other respiratory conditions
  • HIV/ AIDS
  • Alcoholism
  • Thyroid disorders
  • Electrolyte imbalances

If you are pregnant, planning to become pregnant, or breastfeeding, consult your healthcare provider before using Bactrim to assess potential risks and benefits.

Are there any other special instructions I should follow?

You can follow your regular diet while taking Bactrim. Talk to your healthcare provider about the use of this drug with food, beverages, alcohol, and tobacco.

Your healthcare provider will provide specific instructions regarding the use of Bactrim with food, beverages, and other medications. It's essential to follow their guidance to ensure the effectiveness of the treatment and minimize the risk of side effects.

What should I do in case of an overdose?

The symptoms of a Bactrim (sulfamethoxazole-trimethoprim) overdose include:

  • Nausea
  • Vomiting
  • Dizziness
  • Confusion
  • Yellowing of the skin or eyes (jaundice)
  • Dark urine
  • Difficulty breathing

If you experience any of these symptoms, call the poison control helpline at 1-800-222-1222. If an individual has collapsed, is having seizures, or is unresponsive, call 9-1-1 immediately.