What are the intramuscular (IM) doses for streptococcal pharyngitis (strep throat)?

From the Guidelines

For strep throat, a single intramuscular injection of benzathine penicillin G is the recommended treatment, with a dose of 1.2 million units for adults and 600,000 units for children weighing less than 60 pounds (27 kg), as supported by the most recent and highest quality study 1.

Key Points

• The recommended dose is based on the patient's weight, with 600,000 units for children under 60 pounds and 1.2 million units for adults and children over 60 pounds.
• Benzathine penicillin G is the preferred treatment due to its ability to maintain therapeutic blood levels for 2-4 weeks, effectively eradicating group A streptococcal infection.
• Patients should be screened for penicillin allergy before administration, and alternative treatments such as oral antibiotics like clindamycin or macrolides should be considered for those with allergies.
• The injection is typically given in the gluteal muscle and may cause pain at the injection site.

Benefits and Considerations

• Benzathine penicillin G is a convenient and effective treatment option, particularly for patients who may have difficulty adhering to oral antibiotic regimens.
• The treatment has been shown to prevent initial attacks of acute rheumatic fever, a potential complication of strep throat.
• However, it is essential to note that benzathine penicillin G may not be suitable for patients with penicillin allergies, and alternative treatments should be considered in such cases.

Evidence Summary

• The recommendation is based on the most recent and highest quality study 1, which provides evidence for the effectiveness of benzathine penicillin G in treating strep throat and preventing acute rheumatic fever.
• Earlier studies 1 and 1 also support the use of benzathine penicillin G, but the most recent study 1 provides the strongest evidence for its effectiveness.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Streptococcal (Group A) Upper Respiratory Infections (for example, pharyngitis) Adults—a single injection of 1,200,000 units; older pediatric patients—a single injection of 900,000 units; infants and pediatric patients under 60 lbs. —300,000 to 600,000 units. The intramuscular (IM) doses for streptococcal pharyngitis (strep throat) are:

• Adults: 1,200,000 units as a single injection
• Older pediatric patients: 900,000 units as a single injection
• Infants and pediatric patients under 60 lbs: 300,000 to 600,000 units as a single injection 2

From the Research

Intramuscular (IM) Doses for Streptococcal Pharyngitis

• The recommended IM dose for streptococcal pharyngitis is benzathine penicillin G 3, 4, 5
• The study from 2007 recommends only oral penicillin V or intramuscular benzathine penicillin G as the drugs of choice for treatment of group A beta-hemolytic streptococcal (GABHS) pharyngitis 3
• A study from 2011 compared oral amoxicillin to intramuscular benzathine penicillin G (IM BPG) and found that IM BPG may be preferable for treatment of GAS pharyngitis if compliance is a major issue 4
• The efficacy of benzathine penicillin G in group A streptococcal pharyngitis was reevaluated in a study from 1987, which found that the rate of streptococcal eradication after intramuscular administration of benzathine penicillin G was high 5

Dosage Information

• The exact dosage of benzathine penicillin G is not specified in the provided studies, but it is recommended as a single dose for treatment of GAS pharyngitis 4, 5
• A study from 2003 mentions that a 10-day course of penicillin V is the recommended first-line therapy for streptococcal pharyngitis, but does not provide information on IM doses 6
• A review from 2004 discusses the use of antibiotics for acute group A streptococcal pharyngitis, but does not provide specific dosage information for IM benzathine penicillin G 7