Always used as a fixed dose combination of Trimethoprim-Sulfamethoxazole in ratio of 1:5. Dose of Trimethoprim(TMP) is used for calculation purposes.

Mild to Moderate Infections
  • 4 mg TMP/kg/dose PO – 12 hrly  
Serious Infections
  • ORAL  : 4 mg TMP/kg/dose – 6 hrly 
  • IV dose: 4 mg TMP/kg/dose – 6  hrly as infusion
Acute Otitis Media

Acute otitis media in pediatric patients due to susceptible strains of Streptococcus pneumoniae or Haemophilus influenzae

3-5 mg TMP/kg/dose –  12hrly for 10 days  

Pneumocystis (Carinii) Jiroveci Pneumonia
  • Treatment  : 4 mg TMP/kg/dose Oral/IV – 6hrly for 21 days  
  • Prophylaxis: 75 mg TMP/m²/dose Oral –  12 hrly for 3 days/week on consecutive or alternate days  
  • Oral- 4 mg TMP/kg/dose – 12hrly for 5 days  
  • IV –   4 mg TMP/kg/dose  – 12hr for 5 days
Urinary Tract Infection
  • 4 mg TMP/kg/dose PO – 12hr for 7-14 days if serious infection  
  • 4 mg TMP/kg/dose IV –   12hr for 14 days if serious infection
  • Prophylaxis: 2 mg TMP/kg/dose PO daily  or 5 mg TMP/kg/dose twice weekly
Skin/soft Tissue Infection Due to Community Acquired MRSA (Off-label)

4-6 mg TMP/kg/dose oral 12hrly for 5-10 days; (add beta-lactam antibiotic to regimen if beta-hemolytic Streptococcus spp also suspected) 

Cautions for use

  • Age <2 months
  • Sulfonamides should not be used to treat group A beta-hemolytic streptococcal infections; they will not eradicate streptococcus or prevent rheumatic fever
  • Documented megaloblastic or folate deficiency anemia
  • Hemolysis may occur if administered to patients with G6PD deficiency

Dosage Forms & Strengths


Oral solution

  • Septran / Bactrim* (40mg/200mg)/5mL
  • Septran DS * (80mg/400mg)/5 ml


  • Septran* 80mg/400mg
  • Septran DS/Bactrim Forte* 160mg/800mg

*Disclaimer “All product and company names are trademarks™ or registered® trademarks of their respective holders. Use of them does not imply any affiliation with or endorsement by them” 

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