From the Guidelines
For a patient who did not respond to amoxicillin BID for 10 days, I recommend switching to amoxicillin-clavulanate (Augmentin) 875/125 mg twice daily for 7-10 days, or alternatively, doxycycline 100 mg twice daily for 7-10 days if the patient has a penicillin allergy. Treatment failure with amoxicillin often occurs due to beta-lactamase-producing bacteria or resistant organisms, as noted in the guidelines for acute bacterial rhinosinusitis 1. Amoxicillin-clavulanate addresses this by including clavulanic acid, which inhibits beta-lactamase enzymes that would otherwise destroy the antibiotic.
When prescribing the new regimen, it's essential to reassess the patient's symptoms and consider whether further diagnostic testing might be needed, such as culture and sensitivity testing if available. Patients should complete the full course of the new antibiotic even if symptoms improve quickly. If the infection still doesn't resolve after the second-line treatment, further evaluation including possible referral to a specialist would be warranted to rule out complications or alternative diagnoses. The recommendation for amoxicillin-clavulanate is supported by its calculated clinical efficacy of 90-91% and bacteriologic efficacy of 97-99% in patients with mild disease and no recent antimicrobial use 1. For patients with recent antimicrobial use or moderate disease, amoxicillin-clavulanate at a higher dose (4g/250mg) is recommended, with a calculated clinical efficacy of 91% and bacteriologic efficacy of 99% 1.
In the context of treatment failure, it's crucial to consider the limitations in coverage of the initial antibiotic and the potential for resistant organisms, as highlighted in the guidelines 1. The use of amoxicillin-clavulanate or alternative antibiotics such as doxycycline should be based on the patient's specific situation, including the severity of disease, recent antimicrobial use, and potential allergies.
Key points to consider in managing treatment failure include:
- Reassessing the patient's symptoms and considering further diagnostic testing
- Completing the full course of the new antibiotic
- Evaluating the need for referral to a specialist if the infection does not resolve
- Considering the patient's specific situation, including disease severity and potential allergies, when selecting an alternative antibiotic.
From the Research
Alternative Treatment Options
If a patient did not respond to amoxicillin BID for 10 days, alternative treatment options can be considered:
- Amoxicillin/clavulanate: This combination has been shown to exhibit high antimicrobial activity against amoxicillin-resistant strains of Prevotella species 2
- Clindamycin: This antibiotic has been found to be effective against anaerobic bacteria involved in dentoalveolar infection, including those resistant to amoxicillin 2
- Metronidazole: This antibiotic has also been shown to be effective against anaerobic bacteria involved in dentoalveolar infection, including those resistant to amoxicillin 2
Considerations for Alternative Treatments
When considering alternative treatments, it is essential to take into account the properties and indications of each antibiotic:
- Amoxicillin-clavulanic acid combinations have different ratios available, but comparative effectiveness data for these ratios are scarce 3
- Clavulanic acid is more protein-bound and less heat-stable than amoxicillin, and is associated with a higher risk of gastrointestinal side effects, including Clostridium difficile infection 3