What is the dosing for Bactrim (trimethoprim/sulfamethoxazole) for an 8-year-old female patient weighing 62.2 pounds with a urinary tract infection (UTI)?

From the Guidelines

For an 8-year-old female patient weighing 62.2 pounds with a urinary tract infection (UTI), the recommended dosage of Bactrim (trimethoprim/sulfamethoxazole) is 10 mg/kg trimethoprim plus 40 mg/kg sulfamethoxazole, divided into two doses, for 5 days, as per the guidelines 1.

Calculating the Dosage

To calculate the dosage, first, we need to convert the patient's weight from pounds to kilograms. Since 1 pound is approximately equal to 0.45 kilograms, the patient's weight in kilograms is 62.2 * 0.45 = 28 kilograms.

Dosage Calculation

• The recommended dose is 10 mg/kg of trimethoprim and 40 mg/kg of sulfamethoxazole, twice daily.
• For a 28 kg patient, the dose would be 10 mg/kg * 28 kg = 280 mg of trimethoprim and 40 mg/kg * 28 kg = 1120 mg of sulfamethoxazole, twice daily.

Administration

Bactrim is typically available in a fixed combination where the trimethoprim component is 80 mg and the sulfamethoxazole component is 400 mg per single-strength tablet, or 160 mg trimethoprim and 800 mg sulfamethoxazole per double-strength tablet. The suspension form contains 40 mg trimethoprim and 200 mg sulfamethoxazole per 5 mL. Given the calculated dose, the patient would need a formulation that matches the required dose closely. However, since Bactrim's standard formulations may not exactly match the calculated dose for this patient's weight, the closest approximation should be used, and the treatment should be guided by a healthcare provider to ensure the correct dosage is administered.

Treatment Duration and Side Effects

The standard treatment duration for uncomplicated UTIs in children with Bactrim is typically 5 days, as indicated in the guidelines 1. It's crucial to complete the entire course of antibiotics even if symptoms improve before finishing the treatment. Common side effects may include nausea, vomiting, or rash. If severe skin reactions, persistent diarrhea, or no improvement after 3 days occur, a healthcare provider should be contacted immediately. Encouraging increased fluid intake during treatment can help flush bacteria from the urinary tract.

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 10 - 44 20 1 66 30 1½ 88 40 2 or 1 DS tablet

The patient weighs 62.2 pounds, which is between 66-88 pounds, but closer to 88 pounds (40 kg).

• The recommended dose is 2 tablets or 1 double strength tablet every 12 hours for 10 days, based on the weight range provided in the table. 2

From the Research

Dosing for Bactrim (Trimethoprim/Sulfamethoxazole) in an 8-year-old Female Patient

• The patient's weight is 62.2 pounds, and she has a urinary tract infection (UTI).
• According to the studies, the dosing for trimethoprim/sulfamethoxazole is not explicitly stated for an 8-year-old female patient weighing 62.2 pounds 3.
• However, the study by 3 mentions that increased rates of E. coli resistance have made amoxicillin a less acceptable choice for treatment, and studies have found higher cure rates with trimethoprim/sulfamethoxazole.
• Another study by 4 states that trimethoprim-sulfamethoxazole (160/800 mg twice daily for 3 days) is an appropriate first-line therapy for uncomplicated cystitis in adult women, but does not provide dosing information for pediatric patients.
• A study by 5 compares the efficacy, resistance development, and safety of different antimicrobial treatments for acute uncomplicated lower UTI in women, but does not provide specific dosing information for pediatric patients.

Pediatric Dosing Considerations

• The study by 3 mentions that renal parenchymal defects are present in 3 to 15 percent of children within one to two years of their first diagnosed urinary tract infection, and that evaluation of older children may depend on the clinical presentation and symptoms.
• The same study suggests that ultrasonography, cystography, and a renal cortical scan should be considered in children with urinary tract infections.
• However, the study does not provide specific dosing recommendations for trimethoprim/sulfamethoxazole in pediatric patients.

Conclusion Not Provided

As per the instructions, no conclusion or introduction is provided. The information is presented in a factual manner, citing the relevant studies 6, 7, 4, 3, 5.