What is the recommended dosage of cotrimoxazole (trimethoprim/sulfamethoxazole) for a child with a furuncle?

Cotrimoxazole Dosage for Pediatric Furuncle

For a child with a furuncle (skin abscess), administer cotrimoxazole at 8-12 mg/kg/day of trimethoprim (40-60 mg/kg/day of sulfamethoxazole) divided into 2 doses every 12 hours for 7-10 days. 1

Age-Specific Considerations

• Do not use cotrimoxazole in children under 2 months of age due to the risk of kernicterus 1
• For children over 2 months, the standard dosing regimen is well-established and effective 1

Specific Dosing for Skin and Soft Tissue Infections

The Infectious Diseases Society of America specifically recommends 8-12 mg/kg/day based on the trimethoprim component for skin and soft tissue infections, given for 7-10 days 1. This dosing has been validated in clinical trials showing superior outcomes compared to placebo for cutaneous abscesses, with an 80.5% cure rate versus 73.6% with placebo alone 2.

Administration Details

• Divide the total daily dose into 2 equal doses given every 12 hours 1
• The standard formulation contains trimethoprim and sulfamethoxazole in a 1:5 ratio 1
• Treatment duration should be 7-10 days for uncomplicated skin infections 1

Critical Monitoring Requirements

• Obtain a complete blood count at treatment initiation 1
• Repeat monthly during prolonged therapy to assess for hematologic toxicity including neutropenia, thrombocytopenia, and anemia 1
• Monitor for dermatologic reactions, particularly rash, which occurs in approximately 15% of patients 1

Contraindications and Precautions

• Absolute contraindication in infants under 2 months 1
• Use caution in patients with renal insufficiency, hepatic insufficiency, and G6PD deficiency 1
• Known hypersensitivity to sulfonamides or trimethoprim is a contraindication 1
• For G6PD deficiency patients, there is increased risk of hemolytic anemia 1

Common Pitfalls to Avoid

• Do not use double-dose regimens (16-24 mg/kg/day trimethoprim) for simple skin infections, as research shows no additional benefit over standard dosing 3
• Ensure proper adherence counseling, as treatment failure is significantly more likely when medication is not given correctly 3
• For mild rash, temporarily discontinue and restart when resolved; for urticarial rash or Stevens-Johnson syndrome, permanently discontinue 1

Drug Interactions

Exercise caution when using cotrimoxazole with:

• Methotrexate (may increase toxicity) 1
• Anticoagulants, hypoglycemics, thiazide diuretics, and anticonvulsants (require dose adjustments or closer monitoring) 1