What is the first-line antibiotic dosing for a 10-year-old, 46.2 kg patient with a Urinary Tract Infection (UTI)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Article Review Status
Submitted
Under Review
Approved

Last updated: February 17, 2025 • View editorial policy

From the Guidelines

First-Line Antibiotic Dosing for UTI

The first-line antibiotic dosing for a 10-year-old, 46.2 kg patient with a Urinary Tract Infection (UTI) is amoxicillin-clavulanate at 20–40 mg/kg per day in 3 doses or cephalosporin such as cefixime at 8 mg/kg per day in 1 dose 1.

  • The recommended dosing for amoxicillin-clavulanate would be approximately 924-1848 mg per day, divided into 3 doses of around 308-616 mg each.
  • For cefixime, the dosing would be approximately 369 mg per day, given in 1 dose.
  • It is essential to consider local patterns of susceptibility of coliforms to antimicrobial agents when selecting an antibiotic, as there is substantial geographic variability 1.
  • The total course of therapy should be 7 to 14 days, with a minimum duration of 7 days to ensure effective treatment of the UTI 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 and older: Weight Dose – every 12 hours lb kg Tablets 22-44 10-20 1 66-88 30-40 2 or 1 DS tablet 88-110 40-50 2 or 1 DS tablet

For a 10-year-old patient weighing 46.2 kg with a Urinary Tract Infection (UTI), the first-line antibiotic dosing is:

  • 40 mg/kg sulfamethoxazole and 8 mg/kg trimethoprim per 24 hours, given in two divided doses every 12 hours for 10 days.
  • Based on the weight, the dose would be approximately 1848 mg sulfamethoxazole and 369.6 mg trimethoprim per 24 hours.
  • This would translate to approximately 924 mg sulfamethoxazole and 184.8 mg trimethoprim every 12 hours.
  • According to the dosage table, the patient would likely require 2 or 1 DS tablet every 12 hours 2.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.