The majority of pharyngitis cases are caused by viruses. For those attributed to bacterial sources, throat culture is the gold standard for confirmation and group A streptococcus is the main bacterial agent involved¹. For pharyngitis believed to be bacterial in nature, antibiotics are prescribed to reduce the risk of developing rheumatic fever, the duration of symptoms, and transmission to others. For cases where antibiotics are prescribed, the first line medication is penicillin, due to the low resistance of group A streptococcal bacteria to this group of medications. Commonly recommended regimens include:

Penicillin V

Pediatrics

• 40 mg/kg/day (divided BID or TID) to a max of 750 mg x 10 days
• 250 mg BID

Adults

• 300mgTID x 10days or
• 600mgBID x 10days or
• 500mgBID x 10days

Amoxicillin

Pediatrics

• 40 mg/kg/day (divided BID or TID) x 10 days to maximum of 1000 mg/day

Adults

• 500 mg BID x 10 days

An alternative treatment regimen
Common antibiotic regimens require multiple doses per day. This can be difficult for compliance purposes, especially in pediatric patients who may not like to take medications due to the taste and where difficulty with administration of doses at school may be a concern. Recommendations in recent years have included an alternate dosing schedule which allows for a single dose of antibiotic daily for patients. Possible advantages of this approach are improved compliance due to single daily dosing as well as reduced cost for patients and their families. The recommendation is 50 mg/kg once daily to a maximum of 1000mg for 10 days and is appropriate for children > 3 years old and adults.

Bottom line: Amoxicillin 50 mg/kg once daily (max 1000 mg daily) is an acceptable alternative to multiple daily doses of penicillin or amoxicillin for treatment of Group-A streptococcal pharyngitis infections.

References:

1. Caglar D, Kwun R, Schuh A. Mouth and throat disorders in infants and children. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM, editors. Tininalli’s emergency medicine 8th ed. New York: McGraw- Hill; 2016

2. Rx files [Internet]. Pharyngitis: Management considerations; 2017 Mar [cited 2018 May 21]. Available from: http://www.rxfiles.ca/rxfiles/uploads/documents/ABX-Pharyngitis.pdf

3. CDC.gov [Internet]. Group A Streptococcal Disease: Pharyngitis; 2017 Sep 16 [cited 2018 May 21]. Availbale from: https://www.cdc.gov/groupastrep/diseases-hcp/strep-throat.html

4. Gerber MA, Baltimore RS, Eaton CB, Gewitz M, Rowley AH, Shulman ST, et al. Prevention of rheumatic fever and diagnosis and treatment of acute streptococcal pharyngitis. Circulation. 2009 March. 119: 1541-1551.

5. Shulman ST, Bisno AL, Cleg HW, Gerber MA, Kaplan E, Lee G, et al. Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the infectious diseases society of America. Clin Infec Dis. 2012 Nov; 55(10): e86-e102. Available from: https://academic.oup.com/cid/article/55/10/e86/321183

6. Andrews M, Condren M. Once-daily amoxicillin for pharyngitis. J Pediatr Pharmacol Ther. 2010 Oct-Dec. 15(4): 244-248.