From the Guidelines
For a 13-year-old male weighing 27 kg with Group A streptococcal pharyngitis, the recommended dose of oral amoxicillin is 50 mg/kg/day, which would be approximately 1350 mg/day, but since this exceeds the maximum adult dose, the appropriate dosing would be 500 mg twice daily for 10 days, as stated in the guidelines by the Infectious Diseases Society of America 1. The patient's weight is exactly 27 kg, which is the cutoff point for the dosing of benzathine penicillin G, but for amoxicillin, the dose is calculated based on the patient's weight, and the maximum dose should not exceed 1000 mg/day.
- The dose of 50 mg/kg/day is recommended for 10 days, and it can be divided into two or three daily doses.
- The patient should complete the full 10-day course of antibiotics even if symptoms improve before then, as this helps prevent complications like rheumatic fever and ensures complete eradication of the bacteria.
- Amoxicillin is the first-line treatment for Group A strep pharyngitis because it has excellent activity against the bacteria, good oral absorption, and a narrow spectrum that minimizes disruption to normal gut flora.
- The medication should be taken with or without food, and the patient should be encouraged to stay well-hydrated during the course of treatment.
- If the patient has a penicillin allergy, alternative antibiotics such as azithromycin or clindamycin would need to be considered instead, as recommended by the guidelines 1. The most recent and highest quality study supports the use of amoxicillin as the first-line treatment for Group A streptococcal pharyngitis, and the recommended dose is 50 mg/kg/day, not to exceed 1000 mg/day 1.
From the Research
Dose of Oral Amoxicillin for GABHS Pharyngitis
- The dose of oral amoxicillin for Group A beta-hemolytic streptococcal (GABHS) pharyngitis is not explicitly stated in the provided studies for a 13-year-old male patient weighing 27 kilograms.
- However, according to the study 2, amoxicillin can be given in higher doses (up to 40 to 60 mg/kg/day divided twice daily, maximum dose 1 gram twice daily) as first-line therapy.
- For a 27-kilogram patient, the dose would be:
- 40 mg/kg/day: 27 kg x 40 mg/kg = 1080 mg/day, divided twice daily: 540 mg twice daily
- 60 mg/kg/day: 27 kg x 60 mg/kg = 1620 mg/day, divided twice daily: 810 mg twice daily
- It is essential to note that the maximum dose is 1 gram twice daily, so the dose for this patient should not exceed 1000 mg twice daily.
- The American Heart Association recommends once-daily amoxicillin dosing when treating GABHS, as stated in the study 3.
- First-line treatment for GABHS pharyngitis includes a 10-day course of penicillin or amoxicillin, as mentioned in the studies 4 and 5.