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Sulfamethoxazole/trimethoprim

Brand: Bactrim, Septra

Sulfonamide antibioticUsed for: UTI, MRSA infectionsAnti-Infectives
Key warning

Caution: rare but serious skin and blood reactions

Common side effects

  • Nausea
  • Rash
  • Elevated potassium
  • Sun sensitivity
  • Diarrhea

Key interactions & cautions

  • May increase warfarin bleeding risk
  • May raise potassium with ACE inhibitors or ARBs
  • May raise methotrexate toxicity
  • Caution with certain diabetes drugs

Counseling points

  • Drink plenty of water
  • Finish the full course
  • Use sunscreen for sun sensitivity
  • Report rash, blisters, or peeling skin
  • Avoid if sulfa allergy
← Oseltamivir

High-yield study aid for exam prep — not a substitute for the package insert or a pharmacist’s dispensing reference.