ENT  |  Sore Throat Pathway - Episode 1 or 2 of GAS


Sore Throat Pathway - Episode 1 or 2 of GAS

Table: Standard treatment for a patient's first or second case of confirmed GAS pharyngitis:






2012*, 9



Once daily:




Twice daily:

50mg/kg dose once daily

Max dose 1000mg per day

Weight <30kg: 750mg once daily

Weight >30kg: 1000mg once daily

25mg/kg dose twice daily

Max dose 1000mg per day

10 days

Strong, high

Penicillin V


Children <20kg:


Adolescents & Adults >20kg:

250mg two or three times daily


500mg two or three times daily

10 days

Strong, high




Children <30kg:


Children & Adults >30kg:

450mg (600,000 U)


900mg (1,200,000 U)

Single dose

Strong, high

If concern about allergic (lgE mediated§ or anaphylactic) response to beta lactams, use:


Pending Pharmac decision





2.5mg/kg dose twice daily

300mg once daily

150mg twice daily

10 days


Erythromycin ethylsuccinateII,


Children & Adults:

40mg/kg/day in 2-3 divided doses

Max adult daily dose 1000mg

10 days


For people on benzathine penicillin IM prophylaxis who are GAS positive:

Treat with a 10 day course of oral penicillin or amoxicillin.

Check adherence to prophylaxis programme.  Serum penicillin levels will be falling by week three and four post IM long acting benzathine penicillin injection16

Modified from Table Two in Shulman ST 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 Infect Dis. 2012; 55: 1279-12829 © by permission of Oxford University Press.


* The Infectious Diseases Society of America (IDSA) used the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system (see Appendix 3 for description)9

† Amoxicillin can be taken with food whereas oral penicillin V is best absorbed on an empty stomach. Both are equally effective in eradicating GAS.10,11 Lower frequency of antibiotic dosing has been shown to improve adherence.12,13 Amoxicillin is relatively palatable.14

‡ Benzathine penicillin can be given with lignocaine to reduce injection site pain (see page 33 and Appendix 4). It may be marginally more effective than oral penicillin or amoxicillin in eradicating GAS pharyngitis.15

§ IgE-mediated reactions include ANY bronchospasm, angioedema, hypotension, urticarial or pruritic rash.

II Always check for drug interactions before prescribing. In particular, care should be taken when prescribing macrolides to patients taking warfarin and carbamazepine.

¶ The erythromycin currently funded by Pharmac is erythromycin ethyl succinate. There are other erythromycins available with different pharmacokinetic profiles.

** Erythromycin is not recommended in 2012 The Infectious Diseases Society of America (IDSA) Guideline.9 In 2002 the IDSA recommended erythromycin based on a different grading system for clinical guideline recommendations (Appendix 5)

Reference: New Zealand Guidelines for Rheumatic Fever; 2014 Update; pg35

Warfarin and Antibiotics:

Patients taking warfarin should have their INR monitored at the time of treatment change. i.e. both when starting and stopping antibiotics and at day three or four.

Macrolides i.e. erythromycin, azithromycin, roxithromycin, clarithromycin, clindamycin, interact with many drugs by inhibiting an enzyme involved in metabolising approximately 50% of all prescribed drugs. Check for interactions before prescribing these agents (www.medsafe.govt.nz).

Drug interactions with warfarin are of particular importance because they are potentially life threatening. Particular attention should be paid when considering starting warfarinised patients on macrolide antibiotics such as roxithromycin and erythromycin, with which increased symptomatic interactions have been reported.148.

Beta-lactam antibiotics such as penicillin, amoxicillin and augmentin are good choices for patients on warfarin as they only occasionally elevate international normalised ratio (INR). INR monitoring is still required with these comparatively "safe" antibiotics. Specialist advice should be sought concerning patients requiring antibiotic therapy, who have anaphylactic reactions to beta lactam antibiotics and are taking warfarin.

Rifampicin will induce the metabolism of warfarin and will likely result in subtherapeutic INRs.


9. Shulman S 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 Infect Dis. 2012.

10. Lennon DR et al. Once-daily amoxicillin versus twice-daily penicillin V in group A beta-haemolytic streptococcal pharyngitis. Arch Dis Child. 2008; 93: 474-478.

11. Clegg HW et al. Treatment of streptococcal pharyngitis with once-daily compared with twice-daily amoxicillin: a noninferiority trial. Pediatr Infect Dis J. 2006; 25: 761-767.

12. Llor C et al. The higher the number of daily doses of antibiotic treatment in lower respiratory tract infection the worse the compliance. J Antimicrob Chemother. 2009; 63: 396-399.

13. Kardas P. Comparison of patient compliance with once-daily and twice-daily antibiotic regimens in respiratory tract infections: results of a randomized trial. J Antimicrob Chemother. 2007; 59: 531-536.

14. Steele RW et al. Compliance issues related to the selection of antibiotic suspensions for children. Pediatr Infect Dis J. 2001; 20: 1-5.

15. Shulman ST et al. Streptococcal pharyngitis. In: Stevens DL, Kaplan EL (Eds). Streptococcal infections: Clinical Aspects, microbiology and molecular pathogenesis. 2000. New York, Oxford University Press.

16. Kaplan EL et al. Pharmacokinetics of benzathine penicillin G: Serum levels during the 28 days after intramuscular injection of 1,200,000 units. J Pediatr. 1989; 115: 146-150.

Last updated : Friday, August 21, 2015
Next review date : Saturday, August 20,2016

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