Co-Amoxiclav 457mg/5mL Three Times Daily for Acute Tonsillitis/Pharyngitis
Co-amoxiclav (amoxicillin/clavulanic acid) 457mg/5mL three times daily for 7 days is an acceptable treatment option for acute tonsillitis/pharyngitis, though it is not the first-line choice recommended by major guidelines. 1
First-Line Treatment Recommendations
The Infectious Diseases Society of America (IDSA) guideline for Group A streptococcal pharyngitis does not list co-amoxiclav as a first-line agent for routine acute pharyngitis. 1 However, co-amoxiclav is specifically recommended in certain clinical scenarios:
When Co-Amoxiclav Is Appropriate
Chronic GAS carriers requiring eradication: Co-amoxiclav at 40 mg amoxicillin/kg/day in 3 doses (maximum 2000 mg amoxicillin/day) for 10 days is a strong recommendation with moderate-quality evidence for eliminating chronic streptococcal carriage. 1
Recurrent acute pharyngotonsillitis: Research evidence demonstrates that amoxicillin/clavulanic acid (1 g BID for 10 days in adults) achieves comparable bacteriologic eradication rates to clindamycin and is superior to penicillin in patients with recurrent episodes. 2, 3
Treatment failures with penicillin: When patients fail initial penicillin therapy, co-amoxiclav is an appropriate second-line option due to its activity against β-lactamase-producing organisms. 1
Dosing Considerations for Your Regimen
The 457mg/5mL formulation you mention appears to be a pediatric suspension. The appropriate dosing depends on patient age and weight:
Pediatric dosing: For children, the recommended dose is 40-90 mg/kg/day of the amoxicillin component divided into 2-3 doses, with higher doses (90 mg/kg/day) reserved for more severe infections or areas with resistant organisms. 1
Duration: While 7 days may be effective based on some evidence showing shorter courses (3-7 days) can achieve clinical cure, 1, 4 the IDSA guideline for chronic carriers specifically recommends 10 days for co-amoxiclav. 1
Important Caveats
Gastrointestinal side effects: Co-amoxiclav has significantly higher rates of gastrointestinal adverse events (particularly diarrhea) compared to amoxicillin alone or cefaclor, occurring in approximately 30% of patients. 5, 3
Not first-line for uncomplicated acute pharyngitis: For routine acute streptococcal pharyngitis without complications, penicillin or amoxicillin alone remains the preferred first-line treatment due to narrower spectrum, lower cost, and fewer side effects. 1
Consider patient history: The regimen is most justified when the patient has received amoxicillin in the previous 4-6 weeks, has recurrent infections, or has failed initial penicillin therapy. 1
Clinical Efficacy
Research demonstrates that 3-day treatment with co-amoxiclav achieved a 98.1% clinical response rate in pediatric pharyngolaryngitis/tonsillitis, though bacteriologic eradication was lower (65.4%) compared to 10-day amoxicillin (85.4%). 4 Importantly, even when bacteria persisted, clinical relapse was rare and no cases of acute glomerulonephritis occurred. 4
In summary, while your proposed regimen of co-amoxiclav 457mg/5mL three times daily for 7 days is acceptable and will likely achieve clinical cure, extending to 10 days would align better with guideline recommendations, particularly if treating chronic carriage or recurrent disease. 1