Summary
The regulation of circulatory pressor responses during anti-hypertensive therapy with slow calcium-channel blockers was evaluated in a single-blind placebo-controlled study of two such agents, nifedipine and nicardipine. In twelve patients with stable essential hypertension the dose-response effects of each drug on the resting blood pressure together wth the pressor responses induced by skin cold, isometric exertion and dynamic exercise were examined. Nifedipine or nicardipine were administered in a logarithmic dosage schedule of 15, 30 and 60 mg/day with incremental doses at weekly intervals. The effects on resting blood pressure and heart rate at rest and during the three pressor stimuli were measured at each dcse level.
Both drugs induced significant doserelated reductions in the resting diastolic blood pressure without change in pulse pressure, accompanied by an increase in heart rate; in the small numbers in the present study there were no significant differences evident between the doseresponse effects of nifedipine and nicardipine. There was a small reduction in the systolic pressor response to hand cold on nifedipine; the increases in blood pressure and heart rate induced by hand-grip contraction or sub-maximal treadmill walking were unaffected by either drug. These studies suggest that calcium antagonists, by reducing the resting blood pressure, without impairing the circulatory responses to daily activities, have a potentially important therapeutic role in the management of essential hypertension.
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The authors wish to thank Miss A. Storey, BSc,
The authors wish to thank Miss A. Storey, BSc,
The authors wish to thank Miss A. Storey, BSc,
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Silke, B., Ahuja, R.C., Okoli, R.C. et al. Blockade of slow calcium channels and regulation of circulatory pressor responses in uncomplicated hypertension. I.J.M.S. 152, 364–372 (1983). https://doi.org/10.1007/BF02960746
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DOI: https://doi.org/10.1007/BF02960746