Alternate Day Prophylactic Dose of Septran DS for Children
The recommended alternate day prophylactic dose of Septran DS (trimethoprim-sulfamethoxazole) for children is 8 mg/kg/day of trimethoprim component, which can be administered three consecutive days per week as an alternative to daily administration. 1
Dosage Calculation and Administration
- For prophylaxis in children, the FDA recommends 750 mg/m² per day of sulfamethoxazole with 150 mg/m² per day of trimethoprim given orally in equally divided doses twice a day, on 3 consecutive days per week 2
- The total daily prophylactic dose should not exceed 1600 mg sulfamethoxazole and 320 mg trimethoprim 2
- For children older than 2 months, the dose is calculated based on the trimethoprim component at 8 mg/kg/day divided into two doses 1, 2
- For a standard prophylactic regimen, this dose can be administered on alternate days or three consecutive days per week 1
Administration Guidelines by Age/Weight
- Infants less than 2 months of age: Trimethoprim-sulfamethoxazole is contraindicated 3, 2
- Children 2 months and older: Use weight-based dosing of 8 mg/kg/day of trimethoprim component 1, 2
- Dosing guide by body surface area (for 3 days per week prophylaxis) 2:
- Body surface area 0.26-0.53 m²: ½ tablet every 12 hours
- Body surface area 1.06 m²: 1 tablet every 12 hours
Indications for Prophylaxis
- Prophylaxis for Pneumocystis jiroveci pneumonia in immunocompromised children 1
- Prevention of recurrent urinary tract infections 4, 5
- Post-exposure prophylaxis for certain infections (as an alternative agent) 1
Monitoring and Safety Considerations
- Regular monitoring should include complete blood counts with differential and platelet counts at initiation of prophylaxis and monthly thereafter 1
- Long-term low-dose prophylaxis has proven very effective with minimal adverse effects in children 4, 5
- The incidence of adverse reactions in children on prophylactic doses is significantly lower than in those on full therapeutic doses 5
- Common side effects include rash, gastrointestinal disturbances, and hematologic abnormalities, though these are rare at prophylactic doses 1, 5
Important Precautions
- Trimethoprim-sulfamethoxazole is contraindicated in infants younger than 2 months due to the potential risk for kernicterus 3, 2
- The drug should be used with caution in patients with impaired hepatic and renal functions 3
- If life-threatening toxicity occurs, the drug should be permanently discontinued 1
- Adequate fluid intake should be maintained to prevent crystalluria and renal stones 3
Clinical Efficacy
- Studies have shown that prophylactic use of trimethoprim-sulfamethoxazole at appropriate doses is highly effective in preventing reinfections 4
- In one study, only 6 of 130 children receiving prophylactic treatment developed reinfection during a total period of 2637 months 4
- The safety profile for long-term prophylaxis in children is excellent, with serious side effects being extremely rare and most being reversible upon discontinuation of therapy 5