Sulfamethoxazole/trimethoprim (often referred to as SMX/TMP, Bactrim, Septra, or co-trimoxazole) is an antibiotic combination used to treat a variety of bacterial infections. Like all medications, it can cause side effects. Not everyone will experience these side effects, and in many patients, the side effects are mild and temporary. However, it’s important to be aware of potential reactions.
Sulfamethoxazole/trimethoprim side effects
Common side effects include:
- Nausea or vomiting
- Diarrhea
- Loss of appetite
- Rash
Less common but more serious side effects include:
- Allergic reactions: Symptoms may include rash, itching, swelling, severe dizziness, or trouble breathing.
- Serious skin reactions: Symptoms can include fever, sore throat, swelling in the face or tongue, burning in the eyes, skin pain, followed by a red or purple skin rash that spreads and causes blistering and peeling.
- Liver problems: Symptoms can include yellowing eyes or skin, persistent nausea or vomiting, dark urine, or persistent fatigue.
- Blood disorders: Symptoms might include easy bruising or bleeding, persistent sore throat, or fever.
- New or worsening cough
- Shortness of breath
- Watery or bloody diarrhea (this could be a sign of a new infection).
- Unusual tiredness
- Signs of low blood sugar (hypoglycemia): Symptoms may include sudden sweating, shaking, fast heartbeat, hunger, blurred vision, dizziness, or tingling hands/feet.
- Kidney problems: Signs might include change in the amount of urine or blood in the urine.
- Mental/mood changes (e.g., depression, hallucinations, confusion)
- Joint pain
- Muscle weakness
- Unusual hair loss
Rare side effects include:
- Severe intestinal condition (Clostridium difficile-associated diarrhea)
- Low blood sodium (hyponatremia): Symptoms might include headache, weakness, unsteadiness, and confusion.
In addition, sulfamethoxazole/trimethoprim can cause changes in laboratory tests, especially liver function tests and complete blood count.
It’s important to note that while these side effects are potential risks, the majority of patients do not experience severe reactions. If you or someone you know is taking sulfamethoxazole/trimethoprim and begins to experience any unusual or severe symptoms, it’s crucial to contact a healthcare professional immediately.
Remember, this is not a complete list of side effects. Always consult with a healthcare professional or pharmacist for detailed information on this medication and potential side effects.
