Scant effect of antihypertensive monotherapy on nocturnal blood pressure in patients with obstructive sleep apnea

Patients with obstructive sleep apnea (OSA) are often hypertensive. About one third of the hypertensive patients suffer from OSA. We compared the antihypertensive effect of four different antihypertensive medications (atenolol 50 mg, hydrochlorothiazide (HCTZ) 25 mg, isradipine SR 2.5 mg, and spirapril 6 mg) on patients with hypertension and partial upper airway obstruction by using the ambulatory blood pressure measurement. Atenolol (13(SD 23) mmHg), isradipine (10(15)) and spirapril (7(17)) decreased the mean 24-hour systolic blood pressure (BP) significantly (p < 0.01). All medications (atenolol 12(SD 14) mmHg, isradipine 7(10), HCTZ 3(14), and spirapril 6(15)) decreased the mean 24-hour diastolic BP significantly (p<0.01). During nighttime none of the medications reduced significantly the mean systolic or diastolic BP. Atenolol and spirapril lost their antihypertensive effect during the early morning hours. The effect of HCTZ lasted only few hours after taking the medication. The circadian curve of isradipine remained quite smooth during the whole 24-hour time. The daytime BP is quite easily contolled by any antihypertensive monotherapy in hypertensive patients with OSA. Instead the reduction of nocturnal BP seems to require either higher doses of monotherapy or combination therapy.