Effect of verapamil sustained-release on the sympathetic nervous system response to isometric stress in patients with essential hypertension: A pilotstudy in Turkish patients
Z. Bicik et al., Effect of verapamil sustained-release on the sympathetic nervous system response to isometric stress in patients with essential hypertension: A pilotstudy in Turkish patients, CURR THER R, 62(8), 2001, pp. 595-601
Citations number
14
Categorie Soggetti
Pharmacology,"Pharmacology & Toxicology
Journal title
CURRENT THERAPEUTIC RESEARCH-CLINICAL AND EXPERIMENTAL
Background: Stress and sympathetic nervous system activation play a major r
ole in the pathogenesis of essential hypertension. Recent data suggest that
the calcium channel blocker verapamil, in addition to its antihypertensive
effects, can alter the level of norepinephrine released during stress.
Objective: The purpose of this study was to examine the effects of verapami
l sustained-release (SR) on the sympathetic nervous system response to stre
ss in patients with essential hypertension.
Methods: Patients with essential hypertension (diastolic blood pressure >90
mm Hg and systolic blood pressure >140 mm Hg) whose blood pressure was ina
dequately controlled or uncontrolled were enrolled in the study. Secondary
hypertension was ruled out by routine biochemical, endocrine, and radiologi
c tests. After a 15-day washout period during which all previous antihypert
ensive medication was discontinued, blood pressure, heart rate, and serum n
orepinephrine levels were measured at rest and in response to stress (ie, i
sometric exercise). Patients began treatment with verapamil SR at dosages r
ecommended in the Sixth Report of the Joint National Committee for the Prev
ention, Diagnosis, Evaluation, and Treatment of High Blood Pressure (240 mg
/d for stage I hypertension and 480 mg/d for stage II and stage III hyperte
nsion). After 4 weeks of treatment, blood pressure, heart rate, and norepin
ephrine levels were measured again at rest and in response to stress.
Results: Thirteen patients (9 women and 4 men) were enrolled; 9 patients co
mpleted the study. Three patients were lost to follow-up and 1 was noncompl
iant. Verapamil SR significantly lowered norepinephrine levels both at rest
and in response to stress (P<0.01), and reduced the increase in norepineph
rine levels after isometric exercise.
Conclusion: These results suggest that in this small sample of Turkish pati
ents, verapamil SR significantly diminished the sympathetic nervous system
response to stress by decreasing norepinephrine levels. This property may m
ake verapamil SR especially useful when there is a need for decreased sympa
thetic activity (and thereby, a reduction in oxygen consumption) as well as
other antihypertensive effects, such as in patients with coronary heart di
sease.