From the Guidelines
For a 25kg child, the recommended dose of Bactrim (sulfamethoxazole and trimethoprim) twice daily is 4 mg/kg trimethoprim plus 20 mg/kg sulfamethoxazole, which translates to approximately 100mg trimethoprim and 500mg sulfamethoxazole per dose, given twice daily. This dosage is based on the guidelines for the treatment of various infections, including otitis media, where co-trimoxazole is recommended at a dose of 4 mg/kg trimethoprim plus 20 mg/kg sulfamethoxazole twice daily for 5 days 1. Key considerations for administering Bactrim to a child include:
- Ensuring the child takes the medication with food to minimize gastrointestinal upset
- Completing the full course of treatment as prescribed, even if symptoms improve before then
- Encouraging adequate hydration to prevent crystallization of the drug in the urine
- Monitoring for common side effects such as rash, nausea, or diarrhea, and seeking medical attention if severe reactions occur. Given the potential for variability in drug dosing based on geographical and age-related factors, using a standardized dosing regimen based on weight, such as the one provided, helps to minimize risks and ensure effective treatment 1.
From the FDA Drug Label
Children: The recommended dose for children with urinary tract infections or acute otitis media is 40 mg/kg sulfamethoxazole and 8 mg/kg trimethoprim per 24 hours, given in two divided doses every 12 hours for 10 days. The following table is a guideline for the attainment of this dosage: Children 2 months of age or older: Weight Dose – every 12 hours lb kg Tablets ... 88 40 2 or 1 DS tablet
The dose for a 25 kg child is not explicitly listed in the provided table, but based on the recommended dose of 40 mg/kg sulfamethoxazole and 8 mg/kg trimethoprim per 24 hours, we can calculate it as follows:
- Sulfamethoxazole: 40 mg/kg * 25 kg = 1000 mg per 24 hours
- Trimethoprim: 8 mg/kg * 25 kg = 200 mg per 24 hours Given in two divided doses every 12 hours, the dose would be:
- Sulfamethoxazole: 1000 mg / 2 = 500 mg every 12 hours
- Trimethoprim: 200 mg / 2 = 100 mg every 12 hours Since the exact dosage for a 25 kg child is not provided in the table, but based on the calculation above, the recommended dose is 500 mg sulfamethoxazole and 100 mg trimethoprim every 12 hours 2.
From the Research
Dosing Information for Bactrim in Children
To calculate the dose of Bactrim (sulfamethoxazole and trimethoprim) for a 25kg child, we need to consider the recommended dosage per weight.
- The typical dosage of Bactrim for children is 8-10 mg/kg/day of trimethoprim, given in two divided doses every 12 hours 3.
- For a 25kg child, the total daily dose would be approximately 200-250 mg of trimethoprim (8-10 mg/kg/day x 25 kg).
- Since Bactrim is usually given in a fixed combination of sulfamethoxazole and trimethoprim, the dose of sulfamethoxazole would be 5 times the dose of trimethoprim, which would be approximately 1000-1250 mg per day.
- Given twice daily, the dose of Bactrim for a 25kg child would be approximately 500-625 mg of sulfamethoxazole and 100-125 mg of trimethoprim per dose.
Important Considerations
- It's essential to note that the dosage of Bactrim may vary depending on the specific infection being treated and the child's renal function 3, 4.
- The studies provided do not give a clear recommendation for the dosage of Bactrim in children for all infections, but they do provide guidance on the pharmacokinetics of trimethoprim and sulfamethoxazole in children and adults 3, 4.
- The dosage of Bactrim should be adjusted based on the child's renal function, as trimethoprim and sulfamethoxazole are excreted by the kidneys 3, 4.
Side Effects and Efficacy
- Bactrim has been shown to be effective in the treatment of various infections, including acute otitis media and uncomplicated skin abscesses 5, 6.
- However, it's also important to consider the potential side effects of Bactrim, including gastrointestinal side effects and the risk of allergic reactions 5, 6.