What is the prophylactic dosage of cotrimoxazole (Trimethoprim/Sulfamethoxazole) for a 15kg child with Human Immunodeficiency Virus (HIV)?

From the Guidelines

The recommended prophylactic dosage of cotrimoxazole for a 15kg child with HIV is 150/750 mg/m2/day in 2 divided doses by mouth, which is approximately 6-8mg/kg/day of trimethoprim component, as recommended by the guidelines for preventing opportunistic infections among HIV-infected persons 1.

Key Considerations

• The dosage is based on the child's weight and should be adjusted upward as the child grows.
• Cotrimoxazole prophylaxis is essential for HIV-infected children as it prevents Pneumocystis jirovecii pneumonia (PCP), toxoplasmosis, and other opportunistic infections.
• The medication should be taken consistently at the same time each day, preferably with food to minimize gastrointestinal side effects.
• Parents should be advised to watch for potential side effects including rash, nausea, or vomiting, and to ensure adequate hydration while on this medication.

Administration and Monitoring

• The total daily dose should not exceed 320 mg TMP with 1600 mg SMX.
• Prophylaxis should continue indefinitely unless specifically discontinued by the healthcare provider based on immune recovery or other clinical factors.
• Alternative regimens, such as dapsone or atovaquone, may be considered in cases of intolerance or resistance to cotrimoxazole 1.

Evidence-Based Recommendations

• The guidelines for preventing opportunistic infections among HIV-infected persons recommend cotrimoxazole as the first-line prophylaxis for PCP 1.
• The American Academy of Pediatrics and the Infectious Diseases Society of America also recommend cotrimoxazole as the preferred prophylaxis for PCP in HIV-infected children 1.

From the FDA Drug Label

For children, the recommended dose is 750 mg/m2/day sulfamethoxazole with 150 mg/m2/day trimethoprim given orally in equally divided doses twice a day, on 3 consecutive days per week The total daily dose should not exceed 1600 mg sulfamethoxazole and 320 mg trimethoprim The following table is a guideline for the attainment of this dosage in children: Body Surface Area Dose – every 12 hours (m2) Tablets 0.26 - 0.53 ½

1. 06 1

To calculate the dosage, we need to calculate the body surface area (BSA) of the child.

• The formula to calculate BSA is: BSA (m2) = sqrt((height (cm) x weight (kg)) / 3600)
• However, since we only have the weight of the child (15kg) and not the height, we cannot calculate the BSA directly.
• We cannot provide a definitive answer without the height of the child or more information about the child's BSA. 2

From the Research

Prophylactic Dosage of Cotrimoxazole for a 15kg Child with HIV

• The World Health Organization (WHO) recommends cotrimoxazole prophylaxis for HIV-infected children, but the optimal dosage is not clearly established 3.
• A study published in 2001 found that lower doses of trimethoprim-sulfamethoxazole (TMP-SMX) than recommended by the Centers for Disease Control (CDC) were effective in preventing Pneumocystis carinii pneumonia (PCP) in children with HIV/AIDS 4.
• A 2017 study found that the WHO-recommended dose of cotrimoxazole may not provide adequate exposure to the drug in children, and proposed a dosing scheme based on body weight 5.
• For a 15kg child, the proposed dose would be 25mg/kg of sulfamethoxazole (SMX) and 5mg/kg of trimethoprim (TMP) 5.
• This would translate to a total daily dose of 375mg of SMX and 75mg of TMP for a 15kg child.

Considerations

• The use of cotrimoxazole prophylaxis in HIV-exposed but uninfected children is not recommended, as it has been shown to offer no survival benefit in non-malarial, low-breastfeeding areas with a low risk of mother-to-child transmission of HIV 6.
• Cotrimoxazole prophylaxis has been associated with a low risk of severe anemia and neutropenia in HIV-exposed uninfected infants, but this risk is not significant enough to limit its use 7.