Please check your internet connection and try again.
## Septran (Co-trimoxazole)
**Overview**
Co-trimoxazole is a combination antibiotic, typically a 5:1 ratio of sulfamethoxazole and trimethoprim.
**Primary Indications**
* Urinary tract infections (UTIs)
* Pneumocystis jirovecii pneumonia (PCP) prophylaxis and treatment
* Certain respiratory tract infections, ear infections, and gastrointestinal infections.
**Adult Dosing**
* **UTIs:** 1 DS (double strength) tablet every 12 hours for 3-7 days.
* **PCP Prophylaxis:** 1 DS tablet daily.
* **PCP Treatment:** 15-20 mg/kg/day of trimethoprim component, divided into 3-4 doses, for 14-21 days. This typically translates to 2 DS tablets every 6-8 hours.
* **General Infections:** 1 DS tablet every 12 hours. May increase to 2 DS tablets every 12 hours for severe infections.
**Pediatric Dosing**
Dosing is based on the trimethoprim component, typically 8-10 mg/kg/day divided into two doses. The sulfamethoxazole dose will be approximately 40-50 mg/kg/day.
* **UTIs and other infections:** 8-10 mg/kg/day of trimethoprim divided into two doses. For example, a 20 kg child would receive approximately 160-200 mg of trimethoprim daily, usually given as 1/2 to 1 DS tablet twice daily.
* **PCP Prophylaxis:** 5 mg/kg/day of trimethoprim, divided into two doses, given on 3 consecutive days per week, or daily.
* **PCP Treatment:** 15-20 mg/kg/day of trimethoprim, divided into 3-4 doses.
**Dose Adjustments**
* **Renal Impairment:** Adjust dose based on creatinine clearance (CrCl).
* CrCl > 30 mL/min: No adjustment.
* CrCl 15-30 mL/min: Half the usual dose.
* CrCl < 15 mL/min: Avoid use or administer with caution, monitor closely.
**Contraindications**
* Known hypersensitivity to trimethoprim or sulfonamides.
* History of drug-induced thrombocytopenia with either agent.
* Documented megaloblastic anemia due to folate deficiency.
* Premature infants and infants during the first 2 months of life (increased risk of kernicterus).
* Severe renal insufficiency when sequential and measurable monitoring of plasma concentrations cannot be made.
* Patients with porphyria.
**Adverse Effects**
Common: Nausea, vomiting, rash, Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), aplastic anemia, agranulocytosis, leukopenia, thrombocytopenia, hyperkalemia, hyponatremia, photosensitivity, hepatitis, crystalluria.
**Key Drug Interactions**
* **Warfarin:** Increased INR. Monitor INR closely and adjust warfarin dose.
* **ACE inhibitors/ARBs/Potassium-sparing diuretics:** Increased risk of hyperkalemia.
* **Methotrexate:** Increased methotrexate levels and potential for toxicity.
* **Potassium supplements/Potassium-containing salt substitutes:** Increased risk of hyperkalemia.
* **Digoxin:** Increased digoxin levels.
* **Cyclosporine:** Increased cyclosporine levels.
* **Oral contraceptives:** Reduced efficacy. Consider alternative contraception.
* **Potent CYP2C8 inhibitors (e.g., gemfibrozil):** Increased plasma concentrations of sulfamethoxazole.
**Monitoring**
* **Renal function:** Baseline and periodically, especially in patients with renal impairment.
* **Complete blood counts (CBC):** Baseline and periodically, especially in patients with G6PD deficiency, suspected folate deficiency, or prolonged therapy.
* **Electrolytes:** Particularly potassium.
* **Liver function tests:** Periodically, especially in patients with liver disease.
* **Signs of hypersensitivity reactions:** Monitor for rash, fever, and other signs.
* **Therapeutic drug monitoring:** May be indicated in severe infections or renal impairment.
**Clinical Pearls**
* Advise patients to drink plenty of fluids to prevent crystalluria.
* Photosensitivity is common; advise patients to use sun protection.
* Discontinue immediately if rash develops.
* Caution in patients with G6PD deficiency due to risk of hemolytic anemia.
* Monitor infants closely for jaundice.
This information is intended for healthcare professionals. Always consult the most current prescribing information and relevant guidelines for complete details and to ensure appropriate patient care.
