Cardiovascular effects of mibefradil in hypertensive patients with obstructive sleep apnea

Hypertension is often seen in obstructive sleep apnea (OSA) and is characterized by increased sympathetic activity, depressed baroreflex and accentuated vascular responsiveness. The objective of this study was to investigate the effects of the new T-selective calcium channel blocker mibefradil on invasively measured blood pressure (BP) and heart rate in hypertensive patients with OSA.

The present study was a double-blind, randomized and placebo-controlled before and after trial in two parallel groups. Fifty-three men aged 23 69 years with systemic hypertension and OSA were recruited from the Outpatient Department of the Marburg University Sleep Laboratory and hospitalized for 10 days. Mibefradil (50 mg) or placebo were given orally in the morning for 8 days. The main outcome measure was the mean arterial (radial) BP monitored continuously during nocturnal sleep and during standardized daytime physical and psychological performance testing.

Mibefradil lowered mean arterial BP and heart rate with (SD) during the entire measurement period compared with placebo: -7.25 (9.59) vs -2.11 (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 performance testing, including graded exercise. Adverse events did not differ compared with placebo.

Mibefradil is an effective but well-tolerated antihypertensive that also lowers heart rate over 24 h in OSA, in conditions known to increase BP.