Cardiovascular effects of mibefradil in hypertensive patients with obstructive sleep apnea

Objective: Hypertension is often seen in obstructive sleep apnea (OSA) and is characterized by increased sympathetic activity, depressed baroreflex an d accentuated vascular responsiveness. The objective of this study was to i nvestigate the effects of the new T-selective calcium channel blocker mibef radil on invasively measured blood pressure (BP) and heart rate in hyperten sive patients with OSA. Methods: The present study was a double-blind, randomized and placebo-contr olled before and after trial in two parallel groups. Fifty-three men aged 2 3-69 years with systemic hypertension and OSA were recruited from the Outpa tient Department of the Marburg University Sleep Laboratory and hospitalize d for 10 days. Mibefradil (50 mg) or placebo were given orally in the morni ng for 8 days. The main outcome measure was the mean arterial (radial) BP m onitored continuously during nocturnal sleep and during standardized daytim e physical and psychological performance testing. Results: Mibefradil lowered mean arterial BP and heart rate with (SD) durin g the entire measurement period compared with placebo: -7.25 (9.59) vs -2.1 1 (8.43) mmHg (P = 0.039) and -4.83 (5.94) vs -1.34 (4.13) bpm (P = 0.022), respectively. Both effects were observed during nocturnal sleep and perfor mance testing, including graded exercise. Adverse events did not differ com pared with placebo. Conclusion: Mibefradil is an effective but well-tolerated antihypertensive that also lowers heart rate over 24 h in OSA, in conditions known to increa se BP.