TMP/SMX Pediatric Dosage Calculator
Trimethoprim-sulfamethoxazole dosing for UTIs, AOM, PCP prophylaxis, and other infections in children.
Weight in kilograms
Clinical indication
⚠️ Warnings & Contraindications
- Contraindicated in infants <2 months and G6PD deficiency
- Sulfa allergy is common - verify before prescribing
- May cause hyperkalemia, especially with ACE inhibitors or renal dysfunction
- Stevens-Johnson syndrome risk (rare but serious)
- Photosensitivity may occur
- Maintain adequate hydration to prevent crystalluria
- May increase warfarin effect and phenytoin levels
ℹ️ Clinical Notes
Suspension: 40mg TMP/200mg SMX per 5mL (48 mL bottle). SS tablet: 80mg TMP/400mg SMX. DS tablet: 160mg TMP/800mg SMX. TMP/SMX ratio is always 1:5. Dose is expressed by TMP component.
References
- TMP/SMX pediatric dosing - Drugs.com (2026)
- TMP/SMX dosing in children - WikEM (2026)
Medical Disclaimer
This calculator is provided for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or calculated using this tool.
The authors and publishers of this calculator make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability, or availability of the information, products, services, or related graphics contained within this tool for any purpose.