Drug information on Bactrim (100mg/20mg) (Sulphamethoxazole 100mg + Trimethoprim 20mg) from AHPL

•  Skin: Rashes, itching, photosensitivity (sensitivity of the skin to sunlight), rarely serious skin reactions like Stevens Johnson syndrome and epidermal necrolysis.

•  Gastrointestinal System: Nausea, vomiting, glossitis and gastrointestinal discomfort, diarrhea.

•  Liver: Alterations in liver enzymes, cholestatic jaundice (rare).

•  Blood: Reduced blood counts, megaloblastic anemia.

•  Others: Muscle aches, headache, fever, aseptic meningitis, increased serum creatinine and blood urea nitrogen levels (which could indicate reduced kidney function).

Trimethoprim is contraindicated in the following conditions:
• Patients with megaloblastic anemia. Megaloblastic anemia occurs due to folic acid deficiency. Therefore, trimethoprim can worsen the condition.
• Pregnancy, especially in the first trimester due to its interference with folic acid metabolism. Adequate supplementation should be provided in case it is unavoidable.
• Patients allergic to the drug.