Antibiotic therapy for streptococcal pharyngitis and tonsillitis
If possible, collect a throat swab for culture to confirm S. pyogenes infection before starting antibiotic therapy; for discussion on whether empirical antibiotic therapy is indicated and application of culture results, see Approach to managing pharyngitis and tonsillitis in patients at high risk of acute rheumatic fever and Approach to managing pharyngitis and tonsillitis in patients not at high risk of acute rheumatic fever.
If antibiotic therapy for streptococcal pharyngitis and tonsillitis is indicated, use:
phenoxymethylpenicillin 500 mg (child: 15 mg/kg up to 500 mg) orally, 12-hourly for 10 days; see below for further advice on duration of therapy. phenoxymethylpenicillin phenoxymethylpenicillin phenoxymethylpenicillin
S. pyogenes remains highly susceptible to phenoxymethylpenicillin. A 12-hourly dosing regimen for phenoxymethylpenicillin is effective for the treatment of streptococcal pharyngitis or tonsillitis, and is preferred over more frequent dosing regimens because of improved adherence.
Amoxicillin has traditionally not been recommended for sore throat because of concern about an increased incidence of rash if the patient has undiagnosed Epstein–Barr virus (EBV) infection. However, evidence suggests that amoxicillin does not significantly increase the incidence of rash in this settingChew, 2016. Amoxicillin does, however, expose patients to unnecessary broader-spectrum treatment compared to phenoxymethylpenicillin. Therefore, it is not recommended first-line for the treatment of streptococcal pharyngitis and tonsillitis, but has a limited role in children who are unable to tolerate the liquid formulation of phenoxymethylpenicillin.
If amoxicillin is preferred to phenoxymethylpenicillin for a child because the liquid formulation is better tolerated, useNational Heart Foundation of New Zealand, 2019Shulman, 2012The Royal Children's Hospital Melbourne (RCH), Last updated May 2019:
1amoxicillin 50 mg/kg up to 1 g orally, daily for 10 days; see below for further advice on duration of therapy amoxicillin amoxicillin amoxicillin
OR
1amoxicillin 25 mg/kg up to 500 mg orally, 12-hourly for 10 days; see below for further advice on duration of therapy. amoxicillin amoxicillin amoxicillin
Adherence to the full 10-day oral regimen is important for patients at high risk of acute rheumatic fever if aiming to eradicate S. pyogenes from the pharynx and prevent the development of acute rheumatic fever. Intramuscular benzathine benzylpenicillin can be used in those who may experience difficulties adhering to the 10-day oral regimen. It can also be used if oral therapy is not tolerated or a single-dose treatment is preferred by the patient or carer. Use:
benzathine benzylpenicillin intramuscularly1, as a single dose benzathine benzylpenicillin benzathine benzylpenicillin benzathine benzylpenicillin
adult: 1.2 million units (2.3 mL)
child less than 10 kg: 0.45 million units (0.9 mL)
child 10 kg to less than 20 kg: 0.6 million units (1.2 mL)
child 20 kg or more: 1.2 million units (2.3 mL).
Benzathine benzylpenicillin is long acting and provides adequate concentrations of benzylpenicillin for up to 4 weeks, so only a single dose is required. Do not confuse benzathine benzylpenicillin with benzylpenicillin, which is short acting.
For patients who have had a nonsevere (immediate or delayed) hypersensitivity reaction to a penicillin2, use:
cefalexin 1 g (child: 25 mg/kg up to 1 g) orally, 12-hourly for 10 days. For dosage adjustment in adults with kidney impairment, see cefalexin dosage adjustment. See below for further advice on duration of therapy. cefalexin cefalexin cefalexin
For patients who have had a severe (immediate or delayed)3 hypersensitivity reaction to a penicillin, use:
azithromycin 500 mg (child: 12 mg/kg up to 500 mg) orally, daily for 5 days. azithromycin azithromycin azithromycin
Duration of therapy: A 10-day treatment duration is recommended for phenoxymethylpenicillin, amoxicillin and cefalexin to eradicate S. pyogenes from the pharynx and prevent the development of acute rheumatic feverNational Institute for Clinical Excellence (NICE), 2018Shulman, 2012. However, for patients not at high risk of acute rheumatic fever who are being treated for symptom benefit, stopping therapy after 5 days is reasonable if symptoms have resolved and microbiological cure is not neededNational Institute for Clinical Excellence (NICE), 2018. Azithromycin has a long intracellular half-life, so 5 days of therapy is sufficient in all patients.
Ask patients to return if symptoms (particularly fever) do not improve within a reasonable timeframe (eg 3 to 7 days), or if symptoms worsen or new symptoms develop (eg vomiting, dehydration, rigors) at any timeNational Institute for Clinical Excellence (NICE), 2018.
If a rash develops after starting antibiotic therapy, assess the patient for antimicrobial hypersensitivity, but also consider if an alternative diagnosis could explain the rash, such as a viral exanthem, Epstein–Barr virus (EBV) infection, or Arcanobacterium haemolyticum (formerly Corynebacterium haemolyticum) pharyngitis or tonsillitis. For management of A. haemolyticum pharyngitis or tonsillitis, see Antibiotic therapy for Arcanobacterium haemolyticum pharyngitis and tonsillitis.