Medically reviewed by Jessica Swirble, PharmD
Last updated on 4/2/2024

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

The use of sulfamethoxazole-trimethoprim has been shown to cause side effects in some patients.

Common mild side effects of sulfamethoxazole-trimethoprim 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 sulfamethoxazole-trimethoprim. 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.

Tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with sulfamethoxazole-trimethoprim. 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
  
• Sulfonylureas (e.g., glipizide, glyburide)
  
• Digoxin
  
• Cyclosporin
  
• 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 sulfamethoxazole-trimethoprim to assess potential risks and benefits.

You can follow your regular diet while taking sulfamethoxazole-trimethoprim. 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 sulfamethoxazole-trimethoprim 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.

The symptoms of a 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.