A review of antimicrobial stability testing guidance for outpatient parenteral antimicrobial therapy programmes: is it time for global harmonization of testing frameworks?

Antimicrobial stability is an important consideration for treatment planning and service delivery in outpatient parenteral antimicrobial therapy (OPAT) programmes. Regulation of stability assessment varies by region, and conflicting guidance and standards exist. This leads to disparity of equity in access and limits availability of certain antimicrobials for managing infections in the outpatient setting. This review discusses the degree to which the international regulatory bodies have reached consensus on the regulation of antimicrobial stability testing, specifically for OPAT, and describes the variation in antimicrobial recommendations across regulatory bodies. The three major findings in this review are (i) variation in antimicrobial stability testing guidance, particularly in relation to temperature; (ii) lack of regulatory guidance, specifically in that some regions did not have OPAT guidelines; and (iii) only the UK's NHS has provided non-regulatory OPAT-specific advice on antimicrobial stability testing. In conclusion, harmonization of antimicrobial stability testing to form a global OPAT-specific regulatory framework, particularly considering 'areas of variation' amongst current guidance, is required. We call for the development of a global OPAT antimicrobial stability testing framework with consensus from accepted antimicrobial stability criteria, expert opinion and pharmacopoeial best practice.