What is the recommended dosage of antibiotics for acute pharyngitis (strep throat)?

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

Last updated: April 2, 2025 • View editorial policy

From the Guidelines

The standard treatment for strep throat is oral penicillin V at a dose of 250-500 mg two to three times daily for 10 days, as recommended by the most recent and highest quality study 1.

Treatment Options

The dosage for children is typically 250 mg two to three times daily, while adults usually receive 250 mg four times daily or 500 mg twice daily.

  • For patients without penicillin allergy, alternative options include: + Amoxicillin 50 mg per kg once daily (maximum = 1,000 mg) or 25 mg per kg twice daily (maximum = 500 mg) for 10 days, as recommended by 1. + Penicillin G benzathine, intramuscular, with a single dose of 600,000 U for patients weighing less than 60 lb (27 kg) and 1,200,000 U for patients weighing 60 lb or more, as recommended by 1.
  • For patients with penicillin allergy, alternative options include: + Cephalexin (Keflex) 20 mg per kg per dose twice daily (maximum = 500 mg per dose) for 10 days, as recommended by 1. + Azithromycin (Zithromax) 12 mg per kg once daily (maximum = 500 mg) for 5 days, as recommended by 1.

Importance of Completing the Full Course of Antibiotics

It's crucial to complete the full course of antibiotics even if symptoms improve within a few days to prevent complications like rheumatic fever and to ensure complete eradication of the bacteria, as emphasized by 2. While waiting for antibiotics to work, over-the-counter pain relievers like acetaminophen or ibuprofen can help manage throat pain and fever. Adequate hydration and rest are also important components of recovery. The most recent and highest quality study 1 provides the strongest evidence for the recommended treatment options.

From the FDA Drug Label

In the treatment of streptococcal infections of the upper respiratory tract (e.g., tonsillitis or pharyngitis), the therapeutic dosage of erythromycin should be administered for at least ten days. The usual dosage is 30 to 50 mg/kg/day, in equally divided doses. For more severe infections this dosage may be doubled but should not exceed 4 g per day.

The dosage for strep throat is 30 to 50 mg/kg/day of erythromycin, divided into equal doses, for at least 10 days 3.

  • For more severe infections, the dosage may be doubled, but should not exceed 4 g per day.
  • The dosage may vary based on the severity of the infection and the patient's weight.

From the Research

Dosage for Strep Throat

The recommended dosage for strep throat is typically a 10-day course of antibiotics.

  • Penicillin and amoxicillin are first-line antibiotics, with a recommended course of 10 days 4, 5.
  • First-generation cephalosporins are recommended for patients with nonanaphylactic allergies to penicillin 4.
  • There is significant resistance to azithromycin and clarithromycin in some parts of the United States, making them less ideal choices 4.

Important Considerations

  • Guidelines recommend using clinical decision rules to assess the risk of group A beta-hemolytic streptococcal infection, followed by rapid antigen testing if a diagnosis is unclear, before prescribing antibiotics 4.
  • A throat culture is recommended in children and adolescents after a negative rapid antigen test result 4.
  • Patients with worsening symptoms after appropriate antibiotic initiation or with symptoms lasting 5 days after the start of treatment should be reevaluated 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Streptococcal Pharyngitis: Rapid Evidence Review.

American family physician, 2024

Research

Does the choice of antibiotic affect outcome in strep throat?

Annals of emergency medicine, 2015

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.