Please check your internet connection and try again.
# Septran (Co-trimoxazole)
## Overview
Septran is a combination antibiotic containing sulfamethoxazole and trimethoprim. It is a sulfonamide and dihydrofolate reductase inhibitor, respectively, which work synergistically to inhibit bacterial folic acid synthesis.
## Primary Indications
* Urinary tract infections (UTIs)
* Pneumocystis jirovecii pneumonia (PCP) prophylaxis and treatment
* Shigellosis
* Acute exacerbations of chronic bronchitis
* Traveler's diarrhea
* Nocardiosis
## Adult Dosing
* **Uncomplicated UTIs:** 1 DS (double strength) tablet (800 mg sulfamethoxazole/160 mg trimethoprim) every 12 hours for 3-7 days.
* **Complicated UTIs, acute exacerbations of chronic bronchitis, Shigellosis:** 1 DS tablet every 12 hours for 7-14 days.
* **Pneumocystis jirovecii pneumonia (PCP) treatment:** 15 mg/kg/day of trimethoprim component (divided into 3-4 doses) IV or PO for 14-21 days. This typically translates to 1-2 DS tablets every 6-8 hours depending on formulation.
* **PCP prophylaxis:** 1 DS tablet once daily, or 1 DS tablet three times weekly.
* **Traveler's diarrhea:** 1 DS tablet every 12 hours for 5 days.
* **Nocardiosis:** 15-20 mg/kg/day of trimethoprim component (divided into 4 doses) IV or PO for 6 weeks to several months.
## Pediatric Dosing
Dosing is based on the trimethoprim component.
* **UTIs and Shigellosis:** 8 mg/kg/day of trimethoprim component, divided into two doses, given every 12 hours for 7-14 days.
* **PCP treatment:** 15 mg/kg/day of trimethoprim component, divided into 3-4 doses, given every 6-8 hours for 14-21 days.
* **PCP prophylaxis:** 150 mg/m²/day of trimethoprim component, divided into two doses, given every 12 hours for 3 consecutive days per week, or 5 mg/kg/dose of trimethoprim component twice daily.
*Note: Dosing for pediatric patients often relies on specific co-trimoxazole formulations available for children, and exact tablet strength equivalents should be calculated carefully. The DS tablet is typically 800 mg sulfamethoxazole/160 mg trimethoprim.*
## Dose Adjustments
* **Renal Impairment:**
* CrCl > 30 mL/min: No adjustment.
* CrCl 15-30 mL/min: Administer 75% of the usual dose.
* CrCl < 15 mL/min: Avoid use or administer 50% of the usual dose every 12 hours.
## Contraindications
* Known hypersensitivity to trimethoprim or sulfonamides.
* Documented megaloblastic anemia due to folate deficiency.
* Infants less than 2 months of age (risk of kernicterus).
* Severe renal or hepatic insufficiency where frequent laboratory monitoring is not possible.
* History of drug-induced thrombocytopenia with either component.
## Adverse Effects
Common: Nausea, vomiting, rash, urticaria, hyperkalemia.
Serious: Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), severe rash (DRESS syndrome), aplastic anemia, agranulocytosis, severe photosensitivity, cholestatic jaundice, interstitial nephritis, hyperkalemia, hyponatremia, hypoglycemia.
## Key Drug Interactions
* **Warfarin:** Increased INR. Monitor INR closely.
* **Methotrexate:** Increased risk of methotrexate toxicity. Monitor CBC and methotrexate levels.
* **ACE inhibitors/ARBs/Potassium-sparing diuretics:** Increased risk of hyperkalemia.
* **Potassium supplements:** Increased risk of hyperkalemia.
* **Cyclosporine:** Increased risk of nephrotoxicity.
* **Sulfonylureas:** Increased risk of hypoglycemia.
* **Digoxin:** Increased digoxin levels, especially in renal impairment.
## Monitoring
* Complete blood counts (CBC) with differential, especially with prolonged therapy or in immunocompromised patients.
* Renal function (BUN, creatinine).
* Liver function tests (LFTs).
* Electrolytes, particularly potassium.
* Signs of hypersensitivity reactions or rash.
## Clinical Pearls
* Administer with food or milk to minimize gastrointestinal upset.
* Advise patients to drink plenty of fluids to prevent crystalluria.
* Photosensitivity is common; advise sun protection.
* Discontinue at the first sign of rash.
* Trimethoprim can cause a reversible elevation in serum creatinine without affecting glomerular filtration rate (GFR).
***
*This information is intended for healthcare professionals. Always consult the most current prescribing information and local protocols for complete details.*
