Effect of calcium antagonists on stress-induced rise in blood pressure and heart rate: a double-blind, placebo-controlled study

Amlodipine reduces blood pressure during dynamic resistance exercise in hypertensive patients

This study investigated the effect of the dihydropyridine calcium channel antagonist, amlodipine, on blood pressure (BP) during resistance exercise performed at different intensities in hypertensives. Eleven hypertensives underwent 4 weeks of placebo and amlodipine (random double-blinded crossover design). In each phase, they performed knee extension exercise until exhaustion following three protocols: one set at 100% of 1 RM (repetition maximum), three sets at 80% of 1 RM, and three sets at 40% of 1 RM. Intraarterial BP was measured before and during exercise. Amlodipine reduced maximal systolic/diastolic BP values achieved at all intensities (100% = 225 ± 6/141 ± 3 vs. 207 ± 6/130 ± 6 mmHg; 80% = 289 ± 8/178 ± 5 vs. 273 ± 10/169 ± 6 mmHg; 40% = 289 ± 10/176 ± 8 vs. 271 ± 11/154 ± 6 mmHg). Amlodipine blunted the increase in diastolic BP that occurred during the second and third sets of exercise at 40% of 1RM (+75 ± 6 vs. +61 ± 5 mmHg and +78 ± 7 vs. +64 ± 5 mmHg, respectively). Amlodipine was effective in reducing the absolute values of systolic and diastolic BP during resistance exercise and in preventing the progressive increase in diastolic BP that occurs over sets of low-intensity exercise. These results suggest that systemic vascular resistance is involved in BP increase during resistance exercise, and imply that hypertensives receiving amlodipine are at lower risk of increased BP during resistance exercise than non-medicated patients.

Lacidipine

Lacidipine (Caldine, Lacimen, Lacipil, Midotens, Motens) is a once-daily, orally-administered, lipophilic dihydropyridine calcium antagonist with an intrinsically slow onset of activity, resulting in a lack of reflex tachycardia. It has a long duration of action and a high degree of vascular selectivity. In addition to calcium channel-modulated vasodilation, lacidipine displays antioxidant activity greater than that of other dihydropyridine calcium antagonists. In randomised, well-controlled trials, lacidipine 2-6 mg orally once daily had antihypertensive efficacy similar to that of other long-acting dihydropyridine calcium antagonists, thiazide diuretics, atenolol (a beta-blocker) and enalapril (an ACE inhibitor). Lacidipine was effective in elderly patients (including those with isolated systolic hypertension), African Nigerian patients and patients with concurrent type 2 diabetes mellitus. During long-term treatment for 4 or 5 years in patients with isolated systolic hypertension or essential hypertension, the incidence of cardiovascular events and mortality with lacidipine was similar to that with chlorthalidone or atenolol. The European Lacidipine Study on Atherosclerosis (ELSA), in which 2334 patients with hypertension were randomised to 4 years of therapy with lacidipine 4-6 mg/day or the beta-blocker atenolol 50-100 mg/day, demonstrated significantly lower atherosclerotic progression and plaque formation with lacidipine compared with atenolol in patients completing the full 4 years of the study. Between-group differences in favour of lacidipine for the primary efficacy variable (mean change in carotid artery intima-media thickness) did not reach statistical significance in the intent-to-treat population. The tolerability profile of lacidipine (headache, flushing, pedal oedema, dizziness and palpitations) is similar to that of other dihydropyridine calcium antagonists, but with a lower incidence of peripheral oedema. Data from the ELSA study suggest that the incidence of serious adverse events during long-term lacidipine therapy is similar to that with atenolol.

CONCLUSION

Lacidipine is an effective, well tolerated, once-daily, oral antihypertensive agent that can be used in a wide variety of patients. As with other members of its class, lacidipine has shown potentially beneficial antiatherosclerotic effects, although definitive data with respect to possible superiority over other drug classes are still required. Therefore, lacidipine is an attractive therapy for the long-term management of essential hypertension.

[Assessment of the effects of antihypertensive drugs on stress-induced cardiovascular changes]

The authors reviewed some of the most relevant studies dedicated to the assessment of the effects of the antihypertensive drugs on the stress-induced cardiovascular changes. The rises in both blood pressure and heart rate turned out not to be significantly altered by calcium channel blockers, ACE inhibitors, moxonidine, nor beta-blockers, whereas they seemed to be slightly blunted by alpha-blocking drugs. However, since baseline blood pressure was significantly lower in treated hypertensives than in placebo-given patients, all antihypertensive drugs eventually resulted in a lower blood pressure level during stress, as compared with untreated patients. Regarding white coat effect, which has to be considered as a very particular stress, it appeared to be lowered to the same extent by placebo and antihypertensive drugs; moreover, its changes were not associated with any clinical beneficial effect.