Background and Importance Hypertension is among the most frequently diagnosed chronic medical condition in adults. Treatment of hypertension requires one or more drugs (usually thiazide, angiotensin converting enzyme inhibitor (ACEI), angiotensin-II-receptor blocker (ARB), calcium channel blocker (CCB) and/or beta-blockers). Potential drug-drug interactions (pDDIs) are highly prevalent in hypertensive patients receiving multidrug therapy. Knowledge about pDDIs may help physicians minimise adverse effects by careful choice of drugs.

Aim and Objectives To analyse pDDIs among hypertensive patients and evaluate the mechanism and severity of potential outcomes of such interactions.

Material and Methods We conducted a cross-sectional study during a two months period, which included 350 patients with hypertension, treated in university hospita, who had ≥2 medications prescribed. Approval was granted by the Ethics Committee of the hospital. Medication prescriptions were analysed for clinically relevant pDDIs using Lexi-Interact database (Lexi-Comp, Inc, Hudson, Ohio. Statistical analyis was performed using the software PASW Statistics (PASW Inc., Chicago, IL, USA) version 22 and Microsoft Excel® 2010. An expert group, consisting of two clinical pharmacists and two hospital pharmacists, assessed the benefits and risks of each prescribed drug by using the Medication Appropriateness Index. Discontinuation or substitution with another drug with less interacting potential was suggested.

Results A total of 350 patients were included in this study, with average age 77 (36–98) years and 6.1 (2.5) medications. The majority of patients (86.0%) had at least one clinically significant pDDI, average was 3.78 (range 1–25). Suggestions for treatment change aimed mainly at eliminating drug duplications, reducing the use of thiazide diuretics, sulfonylureas, alpha-lipoic acid and pentoxiphylline and increasing the use of calcium-channel blockers, when appropriate. pDDIs would have decreased to 2.10, p<0.001, yet male gender, ≥ 6 medications, cardiovascular diseases, diabetes, benign prostatic hyperplasia, would be predictive of ≥2 pDDIs. The main potential adverse outcomes of pDDIs were hypotension, renal failure, hypoglycemia, bradycardia and lactic acidosis.

Conclusion and Relevance Careful choice of drugs can reduce, but not eliminate pDDIs in hypertensive patients. Close monitoring for hypotension, renal failure, hypoglycemia, bradycardia and lactic acidosis is necessary.

References and/or Acknowledgements 1. Burnier M, Polychronopoulou E, Wuerzner G. Hypertension and drug adherence in the elderly. Frontiers in cardiovascular medicine. 2020;7:49.

Conflict of Interest No conflict of interest.