Is co-amoxiclav (amoxicillin/clavulanic acid) a suitable treatment option for bacterial tonsillitis?

Co-amoxiclav for Bacterial Tonsillitis

Co-amoxiclav (amoxicillin/clavulanic acid) is an effective and appropriate treatment for bacterial tonsillitis, particularly when penicillin has failed or when beta-lactamase-producing bacteria are suspected, though penicillin remains the first-line agent for uncomplicated Group A streptococcal pharyngitis. 1

When Co-amoxiclav Should Be Used

Co-amoxiclav is specifically indicated for tonsillitis in the following scenarios:

• Penicillin treatment failure: When patients have failed previous penicillin therapy for Group A streptococcal tonsillitis, co-amoxiclav demonstrates superior eradication rates (100% vs 70% with penicillin) 2
• Recurrent tonsillitis: In patients with acute recurrent episodes, co-amoxiclav significantly reduces recurrence rates compared to penicillin (2/18 vs 11/19 patients with recurrence over one year) 2
• Beta-lactamase producing bacteria: When beta-lactamase-producing organisms are present (found in >75% of chronically infected tonsils), these bacteria "shield" Group A streptococci from penicillin by inactivating it 3, 4

Dosing Recommendations

Adult dosing:

• Standard dose: 500 mg amoxicillin/125 mg clavulanate three times daily for 10 days 5, 6

Pediatric dosing:

• Standard dose: 45 mg/kg/day of amoxicillin component divided into 2-3 doses 5
• High-dose regimen: 80-90 mg/kg/day of amoxicillin with 6.4 mg/kg/day of clavulanate in 2 divided doses for children with risk factors 5

Clinical Evidence Supporting Use

Bacteriological efficacy is superior with co-amoxiclav:

• Group A streptococci eradication occurs in 6/7 patients (86%) with co-amoxiclav 7
• In comparative studies, amoxicillin/clavulanate for 5 days achieved 83% long-term eradication, comparable to 10 days of penicillin (77%) 8
• Co-amoxiclav effectively targets both Group A streptococci and beta-lactamase-producing organisms including Staphylococcus aureus, Haemophilus species, and anaerobic bacteria 7

Important Caveats

Penicillin remains first-line for uncomplicated cases:

• The IDSA guideline clearly states that penicillin is still the antibiotic of choice for initial treatment of Group A streptococcal pharyngitis 1
• Co-amoxiclav should be reserved for treatment failures, recurrent infections, or when beta-lactamase producers are suspected 3, 4

Tolerability considerations:

• Mild gastrointestinal side effects (nausea, vomiting, diarrhea) occur in approximately 10% of patients 7
• The 14:1 ratio formulation (higher amoxicillin to clavulanate) reduces diarrhea risk in children 5

Resistance patterns matter:

• Co-amoxiclav is more effective than macrolides (clarithromycin) when macrolide resistance is present (83% vs 14-19% eradication with resistant strains) 8
• All Group A streptococci remain susceptible to penicillin and amoxicillin/clavulanate 1, 6