Septran (Sulfamethoxazole + Trimethoprim (Co-trimoxazole))
Also sold as: Septran, Bactrim, Cotrim, SMZ-TMP, Ciplin
Pregnancy
Cat D
Lactation
Caution
Schedule
H
Forms
Tablet SS 400/80mg +3
Indications
- Uncomplicated UTI (E. coli, Klebsiella)
- Pneumocystis jirovecii pneumonia (PCP) — treatment & prophylaxis
- Shigellosis
- Typhoid (where susceptible)
- Nocardiosis
- Toxoplasmosis prophylaxis (HIV patients)
- Traveller's diarrhea
- Acute exacerbation of chronic bronchitis
Adult Dosing
UTI (uncomplicated)
1 DS tablet (800/160mg) PO BD
3 days (women) / 7-14 days (men)
PCP treatment
15-20 mg/kg/day (TMP component) divided every 6-8 hours PO/IV
21 days
PCP prophylaxis
1 DS tablet PO once daily or 1 SS tablet once daily
Used in HIV, organ transplant, immunosuppressed
Shigellosis
1 DS tablet PO BD
5 days
Pediatric Dosing
AVOID in neonates <4 weeks (kernicterus risk). PCP: 15-20 mg/kg/day TMP component divided Q6H.
Renal Dose Adjustment
| CrCl / eGFR | Dose Adjustment |
|---|---|
| CrCl > 30 mL/min | No adjustment |
| CrCl 15-30 mL/min | 50% of usual dose; use with caution |
| CrCl < 15 mL/min | Avoid (accumulation of toxic metabolites) |
Hepatic Adjustment
Use with caution in severe hepatic impairment; monitor LFTs
Pregnancy & Lactation
Pregnancy: Category D
Avoid in 1st trimester (folate antagonism, neural tube defects) and at term (neonatal kernicterus). Use only if essential in 2nd trimester.
Lactation: Caution
Avoid in neonates/jaundiced/G6PD-deficient infants. Excreted in breast milk.
Top Drug Interactions
| Interacting Drug | Effect | Severity |
|---|---|---|
| Warfarin | Significantly increases INR — major interaction | Major |
| Methotrexate | Additive folate antagonism — pancytopenia risk | Major |
| ACE inhibitors / ARBs / Potassium-sparing diuretics | Hyperkalemia risk | Major |
| Phenytoin | Increased phenytoin levels (inhibits metabolism) | Moderate |
| Sulfonylureas | Enhanced hypoglycemic effect | Moderate |
| Azathioprine / 6-Mercaptopurine | Increased myelosuppression | Major |
DoctorScribe — AI Medical Scribe
Stop looking up Septran — just speak the prescription
"Septran as per dose, BD for 5 days." DoctorScribe writes the full prescription with brand, strength, frequency, and route — auto-applies pediatric weight-based dosing and renal adjustments. Try the live demo.
Side Effects
Common
- Nausea
- Vomiting
- Rash
- Photosensitivity
- Hyperkalemia
Serious / Discontinue If
- Stevens-Johnson syndrome / TEN
- Agranulocytosis / aplastic anemia
- Hepatic necrosis
- Aseptic meningitis
- Nephrotoxicity (crystalluria)
- Kernicterus in neonates
Contraindications
- Sulfonamide allergy
- G6PD deficiency (hemolysis)
- Severe renal/hepatic impairment
- Megaloblastic anemia from folate deficiency
- Neonates <4 weeks
- Pregnancy (1st trimester and at term)
Available Indian Brands
| Brand | Manufacturer | Price (approx) |
|---|---|---|
| Septran DS | GSK | 10 tab ₹28 |
| Bactrim DS | Roche (imported) | 10 tab ₹45 |
| Cotrim DS | Cipla | 10 tab ₹22 |
| Ciplin DS | Cipla | 10 tab ₹25 |
Monitoring Required
- CBC (monthly for prolonged therapy)
- Renal function
- Serum potassium (hyperkalemia risk)
- LFTs
Patient Counseling Points
- Take with plenty of water to prevent kidney stones
- Avoid prolonged sun exposure (photosensitivity)
- Report rash, jaundice, or unusual bruising immediately
- Avoid in pregnancy especially first and last trimester
- Take folic acid supplement if on long-term therapy
Stop Googling drug references mid-consultation
EasyClinic auto-flags Septran interactions, renal cutoffs, and pregnancy warnings the moment you write the prescription. Built-in safety net for every Indian doctor.
Clinically reviewed by: Dr. Sanjay Mehta, MD (Internal Medicine), Senior Consultant
Last reviewed: 2026-04-01
References
- BNF — Co-trimoxazole
- WHO HIV Treatment Guidelines 2024
- IDSA PCP Guidelines
- IAP Standard Treatment Guidelines 2024