Cotrimoxazole Syrup Dosage for Acute Febrile Illness (AFI)
For acute febrile illness in children, cotrimoxazole syrup should be dosed at 8 mg/kg/day of trimethoprim plus 40 mg/kg/day of sulfamethoxazole, divided into two doses daily for 5 days. 1
Indications and Usage
Cotrimoxazole (trimethoprim-sulfamethoxazole) syrup is primarily indicated for:
- Acute otitis media: 5-day course 1
- Urinary tract infections: 10-day course 1
- Shigellosis: 5-day course 1
For acute febrile illness without a clear source, cotrimoxazole may be considered when bacterial infection is suspected, particularly in resource-limited settings. However, it's important to note that amoxicillin is generally preferred as first-line therapy for non-severe pneumonia, which is a common cause of febrile illness in children 2.
Dosing Guidelines
Standard Dosing
- Children: 8 mg/kg/day trimethoprim + 40 mg/kg/day sulfamethoxazole divided into 2 doses 1
- Duration: 5 days for most acute febrile illnesses 1
Alternative Dosing for PCP Prophylaxis
- 150 mg/m²/day trimethoprim + 750 mg/m²/day sulfamethoxazole in 2 divided doses, given 3 consecutive days per week 2
Efficacy Considerations
Clinical evidence shows that:
- Amoxicillin has better treatment success rates (91.91%) compared to cotrimoxazole (60.95%) for non-severe pneumonia 3
- However, compliance with cotrimoxazole (90.47%) may be better than with amoxicillin (83.84%) 3
- Cost of cotrimoxazole is approximately 2.3 times lower than amoxicillin 3
Contraindications and Precautions
Cotrimoxazole should NOT be used in:
- Infants younger than 2 months (risk of kernicterus) 1
- Patients with known hypersensitivity to trimethoprim or sulfonamides 1
- Third trimester of pregnancy 1
- Severe renal impairment (creatinine clearance <15 mL/min) 1
Dose Adjustments for Renal Impairment
- CrCl >30 mL/min: Standard regimen
- CrCl 15-30 mL/min: Half the usual regimen
- CrCl <15 mL/min: Not recommended 1
Monitoring and Adverse Effects
Common adverse effects include:
- Gastrointestinal disturbances (nausea, vomiting, diarrhea)
- Rash
Rare but serious adverse effects:
- Stevens-Johnson syndrome
- Blood dyscrasias
- Hepatic necrosis 1
Monitor complete blood counts with differential and platelet count at initiation and monthly thereafter for prolonged use 1.
Clinical Decision Algorithm
- Confirm diagnosis: Assess for signs of bacterial infection warranting antibiotic therapy
- Check contraindications: Verify age >2 months, no sulfa allergy, adequate renal function
- Determine severity: For non-severe infections, oral therapy is appropriate
- Select antibiotic:
- For non-severe pneumonia: Amoxicillin is preferred (50 mg/kg in two divided doses) 2
- For UTI or otitis media where cotrimoxazole is indicated: Use standard dosing above
- Reassess in 48-72 hours: If no improvement, consider treatment failure and switch to alternative therapy
Important Considerations
While cotrimoxazole has historically been recommended for non-severe pneumonia, more recent evidence and guidelines favor amoxicillin as the first-line agent 2. The WHO recommendations from 2009 indicate that "amoxicillin is now preferred to co-trimoxazole as first-line therapy for non-severe pneumonia" 2.
If treatment failure occurs with cotrimoxazole (defined as persistent symptoms after 48-72 hours), consider switching to amoxicillin or amoxicillin-clavulanic acid, particularly for respiratory infections 2.