Resistant hypertension is a common health problem leading to suboptimal cardiovascular prevention. A large number of patients with resistant hypertension have poor medication adherence explaining their assumed resistance to therapy. We combined directly observed therapy (DOT) with therapeutic drug monitoring (TDM) in 3 patients at several time points to enable an extensive feedback on blood pressure (BP) and drug levels. BP was measured with an automatic oscillatory device at regular intervals of 5 minutes (directly before and after drug intake) and at 30-minute intervals (at night) during admission. Blood samples were obtained at different time points (t = in hours; t = 0, 2, 4, 6, 12, and 24 hours after drug intake). DOT was performed under supervision of the physician. In 2 of the 3 patients, automated BP decreased directly after DOT, -10/0 and -5/-5 mm Hg, respectively. Plasma drug levels for several drugs or active metabolites were 0 at t = 0, whereas plasma levels were positive at t = 24 hours after observed intake. We recommend a more frequent use of TDM combined with repeated BP measurements in clinical practice because this is a convenient, objective method of measurement and to ensure that actual drug levels reflect the BP at the time of measurement.,
Journal of Cardiovascular Pharmacology
Department of Cardiology

Feyz, L., Bahmany, S., Daemen, J., van den Meiracker, A., Koch, B., van Gelder, T., & Versmissen, J. (2018). Therapeutic Drug Monitoring to Assess Drug Adherence in Assumed Resistant Hypertension: A Comparison With Directly Observed Therapy in 3 Nonadherent Patients. Journal of Cardiovascular Pharmacology, 72(2), 117–120. doi:10.1097/fjc.0000000000000602