Trimethoprim-Sulfamethoxazole
Uncomplicated UTI, MRSA skin infections, PCP prophylaxis/treatment
Indications
- Uncomplicated UTI
- MRSA skin infections
- PCP prophylaxis/treatment
Adult dosing
- uti: dose: 1; unit: DS tab (160/800mg) PO BID; route: PO; interval: BID x 3 days; fixed: true; mrsa skin: dose: 1; unit: DS tab PO BID; route: PO; interval: BID x 7-10 days; fixed: true; pcp treatment: dose: 15; unit: mg/kg/day TMP component; route: IV/PO divided q6-8h; weightBased: true; maxDose: 1280; maxDoseAbsolute: true
Pediatric dosing
- uti: dose: 8; unit: mg/kg/day TMP component; route: PO divided BID; weightBased: true; maxDose: 320; maxDoseAbsolute: true
Contraindications
- Sulfa allergy
- Severe hepatic/renal impairment
- Megaloblastic anemia due to folate deficiency
Clinical pearls
- First-line for uncomplicated UTI where resistance rates are <20%
- Excellent oral MRSA coverage for skin/soft tissue infections
- Causes hyperkalemia — especially in elderly and with ACE inhibitors/ARBs
- Check G6PD status before use in at-risk populations
Source and review
- IDSA UTI Guidelines; Sanford Guide. Last reviewed: 2024-11-01