Reinhard Gotzen

Antihypertensive and metabolic effects of diltiazem and nifedipine.

The antihypertensive effect of diltiazem (180-270 mg/day) and nifedipine (40-60 mg/day) in slow-release forms was assessed over 8 weeks in a double-blind parallel study in 40 subjects with essential hypertension at rest and during exercise. Blood pressure was comparably reduced in both groups at rest as well as during exercise. The responder rates (greater than or equal to 10% reduction in diastolic blood pressure) after 8 weeks of therapy were 53% at rest and 75% during exercise in the diltiazem group and 78% and 50%, respectively, in the nifedipine group. Diltiazem decreased heart rate by 8% (p less than 0.01), while nifedipine did not affect it. As a consequence, myocardial oxygen consumption, as judged by the pressure-rate product, was reduced by diltiazem. Resting plasma norepinephrine levels were increased significantly after 8 weeks of diltiazem therapy. Plasma epinephrine, renin, aldosterone, glucose, insulin, and lactate and routine laboratory parameters were unchanged at the end of the study. No significant changes in total cholesterol and triglyceride levels were observed after 8 weeks. Whereas therapy with diltiazem resulted in an 8% fall in low density lipoprotein cholesterol after 8 weeks (p less than 0.05), nifedipine induced a drop in very low density lipoprotein cholesterol (p less than 0.05) after 8 weeks of therapy. We conclude that both diltiazem and nifedipine are effective antihypertensive agents lacking undesirable metabolic side effect. Diltiazem, however, had the advantage of lowering heart rate and myocardial oxygen consumption.

Relation of regression of left ventricular hypertrophy to changes in ambulatory blood pressure after long-term therapy with perindopril versus nifedipine

Casual as well as ambulatory 24-hour blood pressure (BP) and echocardiographic parameters were studied in 40 patients with untreated or insufficiently treated mild to moderate essential hypertension. Left ventricular (LV) hypertrophy was assessed before and after 24 weeks of therapy with either the converting enzyme inhibitor perindopril or the calcium antagonist nifedipine. The design was a double-blind parallel study with a placebo run-in period. Patients received a daily oral dosage of either 4 to 8 mg of perindopril or 40 to 80 mg of nifedipine in slow-release form. A diuretic (25 mg/day of hydrochlorothiazide) was added in nonresponders (greater than 90 mm Hg casual diastolic BP). Once-daily perindopril and twice-daily nifedipine comparably reduced both casual and ambulatory BP throughout 24 hours (p less than 0.01) without affecting 24-hour heart rate. Six subjects withdrew from the nifedipine group and 4 from the perindopril group. After 12 and 24 weeks of therapy, LV hypertrophy was significantly reduced by both agents. Before active treatment was begun, LV mass index was more closely correlated to 24-hour (p less than 0.001) than to casual BP. This correlation disappeared after treatment with both agents. The correlation between ambulatory systolic day-time BP and LV mass was only still present (r = 0.54; p less than 0.05) after 24 weeks of treatment with nifedipine. It is concluded that regression of LV hypertrophy during converting enzyme inhibition or calcium antagonism may be partly independent of dosage and magnitude of 24-hour BP decrease.

Functional versus structural changes of forearm vascular resistance in hypertension.

Structural changes in resistance vessels have been considered an important factor in triggering and maintaining chronic hypertension in humans and in experimental animals. To determine whether the increased forearm vascular resistance observed following vasodilator maneuvers in hypertensive patients is predominantly due to structural or to functional changes, we examined the influence of different vasodilator stimuli on forearm blood flow and blood pressure in 22 male patients with established essential hypertension and in 22 age-matched normotensive men (age range, 28-52 years). Blood pressure was measured directly, and blood flow was measured by venous occlusion plethysmography. The maneuvers applied were 1) arterial occlusion combined with handgrip exercise and local heating, 2) intra-arterial infusion of the calcium entry blocker nifedipine, 3) intra-arterial infusion of the nonspecific vasodilator sodium nitroprusside, 4) arterial occlusion initiated after intra-arterial infusion of nifedipine. Vascular resistance during vasodilation induced by arterial occlusion or infusion of nifedipine or sodium nitroprusside remained significantly higher in the hypertensive than in the normotensive subjects. However, the maximal vasodilation achieved by the combination of arterial occlusion and nifedipine resulted in a similar resistance in both groups (1.6 +/- 0.2 in the hypertensive vs 1.4 +/- 0.2 mm Hg/ml/min/100 ml tissue in the normotensive subjects. These data suggest that there is an important functional component of the elevated resistance in patients with essential hypertension.

Crossover Comparison of Nitrendipine with Propranolol in Patients with Essential Hypertension

Summary The antihypertensive effect of nitrendipine (2 × 10 to 2 × 20 mg/day) was compared with that of propranolol (2 × 80 to 2 × 160 mg/day) in a randomized crossover study. Twenty-five patients were treated over two 4-week periods following a placebo period of 2 weeks. Three patients dropped out of the study because of side-effects (two on nitrendipine and one on propranolol). Arterial pressures decreased in a comparable manner from 171/107 mm Hg (measured in a sitting position) to 147/91 mm Hg after 4 weeks on nitrendipine and to 145/93 mm Hg after 4 weeks on propranolol. The frequency of side-effects possibly related to treatment was comparable for both drugs, but decreased with the duration of therapy with nitrendipine only. The antihypertensive effect of nitrendipine, but not of propranolol, correlated positively with age and plasma noradrenaline.

24-hour noninvasive oscillometric blood pressure monitoring: evaluation of the antihypertensive circadian profile of nitrendipine.

The understanding of blood pressure (BP) and heart rate (HR) variation, circadian changes, and the responses to nonclinical situations has been improved by automated ambulatory recordings. The antihypertensive efficacy of a once-daily regimen (10/20 mg) of nitrendipine was evaluated in detail using the lightest available portable device equipped with an oscillometric blood pressure (BP) recorder (SpaceLabs 90202, weight 480 g) devoid of any electrode. A good antihypertensive effect throughout the day in 20 outpatients could be demonstrated. No significant change of BP could be found in early morning and wake-up period; HR was not significantly affected after 6 weeks of oral therapy.

Circadian antihypertensive profile of carvedilol (BM 14190).

Summary: Carvedilol (BM 14190) is a new potent and well‐tolerated &bgr;‐adrenoceptor antagonist with vasodilating properties. Acute clinical studies have confirmed its efficacy as an antihypertensive agent. The present double‐blind, randomized, metoprolol‐controlled, longterm study reports the therapeutic results of carvedilol in essential hypertensive patients. Compared with placebo, carvedilol significantly reduces blood pressure after oral administration of 50 mg on a single and twice daily regimen. The antihypertensive effect was acute in onset, comparable in supine and standing position, and exercise‐induced hypertension and tachycardia were significantly reduced. Indirect automatic 24 h blood pressure monitoring reliably confirmed clinic blood pressure and demonstrated a good antihypertensive effect of carvedilol after a single oral administration throughout daily activities and sleeping periods.

Effects of diltiazem alone and combined with mefruside on cardiovascular response at rest and during exercise, carbohydrate metabolism and serum lipoproteins in patients with systemic hypertension

The antihypertensive effects of the calcium antagonist diltiazem, both alone and combined with the diuretic mefruside, were assessed over 14 months in 36 patients with essential hypertension. Patients received 180 or 270 mg/day; those with inadequate response were given 270 mg/day plus mefruside, 20 mg/day. Both monotherapy and combination therapy significantly reduced blood pressure (BP) at rest and during exercise. However, adding mefruside did not significantly decrease BP below that achieved with diltiazem alone. After 14 months of therapy, the percentage of responders (patients with at least 10% reduction in diastolic BP at rest) was 64% for all patients, 100% (by definition) for those receiving diltiazem alone and 47% for those receiving the combination. Diltiazem decreased heart rate by 6% (4 beats/min at rest) (p less than 0.05). Combined therapy with mefruside did not further reduce heart rate. There were few adverse effects and no undesirable metabolic effects with either monotherapy or combined therapy. Plasma renin activity, aldosterone levels, carbohydrate metabolism, serum lipoprotein levels and routine laboratory test results were unchanged in both groups at the end of the study. Thus, diltiazem is an effective antihypertensive agent and apparently the combination of diltiazem and mefruside does not potentiate the antihypertensive effect of diltiazem alone during long-term therapy.

Nifedipine vasodilates human forearm arteries and dorsal hand veins constricted by specific α-adrenoceptor stimulation

1. The local dilative effect of the calcium entry blocker nifedipine on forearm arteries and dorsal hand veins has been studied in 27 healthy male volunteers. 2. Nifedipine induced an increase of blood flow by 1190% (P less than 0.001) in the forearm. 3. The construction of the hand veins induced by stimulation of either postsynaptic alpha 1- or alpha 2-adrenoceptors was reduced (P less than 0.001) by nifedipine. 4. The calcium entry blocker nifedipine is a potent dilator of human forearm arteries as well as of dorsal hand veins.

Underestimation of 24-hour Hypotensive Efficacy of Nifedipine GITS versus Enalapril: Ambulatory Recording as an Adjunct to Clinical Blood Pressure Measurement

Aims: Short-acting calcium entry blockers should be used primarily in slow-release form. Furthermore, studies of the antihypertensive efficacy of drugs can be negatively influenced by between 15% and 30% of the enrolled patients not being hypertensive according to ambulatory blood pressure (BP) measurement. Thus, a randomized double-blind multicenter parallel-group study was conducted to compare the effect of nifedipine GITS (gastrointestinal therapeutic system) with enalapril. Methods and results

Methodological developments and problems of recorders for automatic, indirect, ambulatory 24-hour monitoring of blood pressure

Blood pressure is a dynamic parameter subject to short-term (e. g., beat-to-beat) and long-term (e. g., circadian rhythm) variation. As early as 1898, Hill (1) was able to register daily blood pressure variations and a permanent blood pressure decrease during sleep by means of indirect palpitation with the aid of a sphygmograph. The auscultation of Korotkoff sounds above the brachial artery (2) — first described in 1905 — and its combination with an occlusion cuff according to Riva-Rocci (3) has become the most widely used procedure for the quantitative assessment of arterial blood pressure in daily routine. Stationary devices use auscultatory procedures by means of a microphone, Doppler sonography or oscillometry introduced by von Recklinghausen (5) in 1940 and different tonometric methods (piezofoils) (Table. 1).