Acute and chronic nitrendipine administration in essential hypertension: a chronobiologic study

Area of Science:

• Cardiology
• Pharmacology
• Chronobiology

Background:

• Arterial hypertension is a prevalent cardiovascular condition.
• Understanding the chronobiologic effects of antihypertensive drugs is crucial for optimizing treatment.
• Nitrendipine is a calcium channel blocker used to manage hypertension.

Purpose of the Study:

• To investigate the chronobiologic pattern of the hypotensive effect of nitrendipine.
• To compare the effects of acute versus chronic nitrendipine administration on blood pressure and heart rate circadian rhythms.

Main Methods:

• A randomized study involving 10 patients with mild-to-moderate arterial hypertension.
• Administration of a single 20 mg dose of nitrendipine, placebo, and 20 mg daily for 2 months.
• 24-hour ambulatory monitoring of systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR).
• Analysis using single and mean cosinor methods, ANOVA, and Student's paired t test.

Main Results:

• Chronic nitrendipine administration significantly lowered SBP and DBP mesor compared to placebo and acute administration.
• The circadian rhythms of SBP and DBP were preserved with chronic nitrendipine treatment.
• The circadian rhythm of HR was maintained, suggesting no interference with neurohormonal mechanisms.

Conclusions:

• Chronic administration of nitrendipine is more effective in reducing blood pressure than acute administration or placebo.
• Nitrendipine preserves the natural circadian variations of blood pressure.
• The drug does not interfere with the heart rate's circadian rhythm, indicating preserved neurohormonal regulation.