Abstract P153: Impact of Antibiotic Treatment on Antihypertensive Drug Adherence

Background: Suboptimal adherence reduces the effectiveness of antihypertensive therapy and is recognised as a significant obstacle in achieving better patient outcomes. The impact of concomitant therapy on adherence levels is unknown. The aim of this study was to identify changes in antihypertensive drug adherence after antibiotic treatment.Methods: We analysed refill prescriptions (2004-2013) from 361,021 patients who attended 2 hospitals in Glasgow. Antihypertensive drug adherence over the preceding and following 12 months of first antibiotic therapy in each patient were analysed. Drug adherence was measured as drug usage over the study period and calculated from the amount of drug dispensed and the defined daily dose for each antihypertensive drug. Comparisons were made using paired-t tests.Results: There were 190,699 subjects prescribed amoxicillin, 63,292 ciprofloxacin, 69,756 clarithromycin and 94,832 trimethoprim. The mean difference in adherence for each antihypertensive drug before and after amoxicillin, clarithromycin, ciprofloxacin and trimethoprim are presented in the Figure. There is a general reduction in adherence following any antibiotic therapy for the antihypertensive drugs studied, with bendrofluomethiazide and atenolol showing the least changes in adherence and doxazosin and ramipril associated with the highest decreases in adherence. No differences between antibiotics was observed for any antihypertensive drug.Conclusion: A single course of antibiotic therapy can have a sustained adverse impact on antihypertensive drug adherence over the following year. The impact of this on BP control and outcomes need to be further study. ![][1] [1]: /embed/graphic-1.gif