From the Guidelines
For a 4-year-old, 45-pound female with a urinary tract infection, the recommended dose of Bactrim (trimethoprim/sulfamethoxazole) is 10 mg/kg trimethoprim plus 40 mg/kg sulfamethoxazole per day, divided into two doses, for 5 days, as per the guidelines 1. This translates to approximately 204 mg of trimethoprim plus 816 mg of sulfamethoxazole per day for this child, or 102 mg trimethoprim plus 408 mg sulfamethoxazole twice daily. Since Bactrim is typically available as a suspension containing 40 mg trimethoprim and 200 mg sulfamethoxazole per 5 mL, the child would need approximately 12.75 mL twice daily, however this may vary based on the formulation and concentration of the suspension. It's essential to complete the full course of antibiotics even if symptoms improve before completion. The medication should be given with plenty of fluids, and parents should ensure the child stays well-hydrated throughout treatment. Bactrim works by inhibiting two consecutive steps in bacterial folic acid synthesis, making it effective against many common UTI-causing organisms. Side effects may include rash, nausea, or diarrhea, and parents should contact their healthcare provider if the child develops a severe rash, persistent vomiting, or if symptoms don't improve within 48-72 hours. It is also crucial to note that the dosage might need adjustment based on the child's response to the treatment and potential side effects, and the healthcare provider's guidance should be followed closely 1. In cases where the child's condition does not improve or worsens, a re-evaluation of the treatment plan may be necessary, considering other antimicrobial agents or adjusting the dosage regimen as needed.
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 22-44 10-20 1 45-88 20-40 2 (400 mg/80 mg) or 1 (DS) tablet
The recommended dose of Bactrim for a 4-year-old, 45-pound female with a UTI is 2 tablets (400 mg/80 mg) or 1 double-strength tablet every 12 hours for 10 days 2.
From the Research
Bactrim Dosing for UTI in Children
To determine the recommended dose of Bactrim (trimethoprim/sulfamethoxazole) for a 4-year-old, 45-pound female with a urinary tract infection (UTI), we must consider the available evidence.
Studies on Bactrim Dosage
- A study from 1989 3 compared single-dose trimethoprim to a 7-day course of co-trimoxazole for treating UTIs in children, but it does not provide specific dosage recommendations for children based on weight.
- Another study from 1970 4 used a dosage of 160 mg of TMP and 800 mg of SM administered orally twice daily for 10 days in adults, which is not directly applicable to a 4-year-old child.
- A 1982 study 5 on single-dose trimethoprim-sulphamethoxazole treatment of symptomatic urinary infection in children does not specify the dosage used.
- A 1988 study 6 found that 100 mg of trimethoprim was the minimum effective dose for treating UTIs in non-pregnant women, but this is for adults and does not provide guidance for pediatric dosing.
- A 1985 study 7 compared single-dose ceftriaxone to multiple-dose trimethoprim-sulfamethoxazole in college women, using 160 mg of trimethoprim-800 mg of sulfamethoxazole orally twice daily for 7 days, which again is not applicable to pediatric patients.
Pediatric Dosage Considerations
Given the lack of direct evidence from these studies for the specific dosage of Bactrim for a 4-year-old, 45-pound female with a UTI, the typical recommendation for pediatric patients is often based on the child's weight. The usual dosage of trimethoprim/sulfamethoxazole for children is 8-10 mg/kg/day of trimethoprim and 40-50 mg/kg/day of sulfamethoxazole, divided into two doses and given for 10 days. However, this information is not derived from the provided studies but rather from general pediatric guidelines.
Calculation of Dosage
Based on general guidelines (not directly from the studies provided), for a 45-pound (approximately 20.4 kg) child:
- The dosage would be approximately 164-204 mg of trimethoprim per day (8-10 mg/kg/day) and 816-1020 mg of sulfamethoxazole per day (40-50 mg/kg/day), divided into two doses.
It's crucial to consult a healthcare provider for the exact dosage, as they can provide guidance based on the most current recommendations and the specific circumstances of the child's infection.