Fixed-dose combination antibiotics: The search for evidence using the example of ampicillin-cloxacillin.

High consumption of irrational fixed-dose combination (FDC) antibiotics may pose a threat of antimicrobial resistance. In India, ampicillin-cloxacillin was the second highest sold FDC antibiotic behind amoxicillin and clavulanic acid. There remain, however, questions about its efficacy and safety and a lack of regulatory approval. We undertook a literature review for ampicillin-cloxacillin to identify available data on the safety and efficacy of its used as FDC. We identified 1071 studies for screening and 81 studies were considered for inclusion. Only 12 studies in English language were accessible full texts for final review. None of the studies identified provided strong evidence that ampicillin-cloxacillin differed in safety or efficacy to other treatments used, and in particular to the component antibiotics used alone. To fully assess the efficacy and safety of ampicillin-cloxacillin and other FDCs, a standardised search format would be required. This should include broad international collaboration, including contacting the relevant regulatory authorities to facilitate a more evidence-based approach to their use.