Effect of Fluconazole on Blood Pressure in Patients Treated with Dihydropyridine Calcium Channel Blockers: A Retrospective Study

Abstract

Fluconazole and dihydropyridine calcium channel blockers (DCCBs) are simultaneously used in clinical practice. Although fluconazole can increase the blood levels of DCCBs by inhibiting CYP3A4, there are only a few reports regarding the effects of interaction of these drugs on blood pressure. Based on electronic medical records, we conducted a retrospective study of blood pressure in hospitalized patients treated with fluconazole while receiving amlodipine and nifedipine. The mean blood pressure over 3 days, specifically 2 days before starting fluconazole treatment and the first day of fluconazole treatment (day 1), was used as the reference value to compare the mean blood pressure calculated every 3 days after day 1 until day 13. Most of the 26 patients included in the study had underlying hematologic malignancies. The average age of patients was 71.8 years. Twenty-one patients received amlodipine and five received nifedipine. The combination of DCCBs and fluconazole was associated with a significant decrease in blood pressure on day 11–13 (p < 0.01). The mean difference in overall systolic blood pressure was −15.8 mmHg (95% CI: −21.1 to −10.4). Therefore, the combination of fluconazole and DCCBs might potentiate the antihypertensive effect of DCCBs, and caution should be exercised when using them for lowering blood pressure.