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Position of calcium antagonists in antihypertensive therapy
Insights
Calcium antagonists effectively lower high blood pressure by reducing intracellular calcium levels. Their efficacy in treating hypertension is influenced by patient age, initial blood pressure, and renin levels, guiding personalized treatment strategies.
Area of Science:
- Cardiology
- Pharmacology
- Hypertension Research
Background:
- Essential hypertension is linked to cellular ion regulation abnormalities, specifically concerning calcium.
- The human platelet serves as a model for vascular smooth muscle cells in studying hypertension.
Purpose of the Study:
- To investigate the relationship between intracellular free calcium concentration and blood pressure in essential hypertension.
- To evaluate the acute and chronic effects of calcium antagonists on blood pressure and vascular resistance.
- To establish a treatment concept for hypertension management using calcium antagonists based on patient characteristics.
Main Methods:
- Utilized human platelets as a model for vascular smooth muscle cells.
- Observed intracellular free calcium concentration and blood pressure.
- Conducted plethysmographical studies to assess vasoconstriction.
- Analyzed chronic monotherapy responses in relation to age, pretreatment blood pressure, and renin levels.
Main Results:
- A direct relationship exists between intracellular free calcium and blood pressure.
- Calcium antagonists acutely lower blood pressure by reducing intracellular calcium and peripheral vascular resistance.
- Antihypertensive response to chronic calcium antagonist monotherapy correlates with age and pretreatment blood pressure, and inversely with renin.
- Sympathetic nerve reflex activation influences the individual antihypertensive outcome.
Conclusions:
- Calcium antagonists are effective antihypertensive agents, particularly for older, low-renin patients, serving as alternatives to diuretics.
- Treatment selection (calcium antagonists, beta-blockers, ACE inhibitors) should be tailored to patient age and renin levels for optimal efficacy.
- Calcium antagonists offer good blood pressure control with minimal adverse effects, alone or in combination therapy.
Abstract:
More than 20 years ago calcium antagonists were shown to lower elevated blood pressure. Today's worldwide recognition, at least in part, is due to rising research interest in cellular ion regulation abnormalities in essential hypertension. Using the human platelet as a model for the vascular smooth muscle cell, a direct relationship was observed between intracellular free calcium concentration and the height of blood pressure before as well as during different antihypertensive treatments. Calcium influx is an important determinant of vasoconstriction, and excess calcium influx-dependent vasoconstriction was shown with plethysmographical studies in patients with essential hypertension. Calcium antagonists acutely lower blood pressure by reducing intracellular calcium and peripheral vascular resistance. The degree of the attendant sympathetic nerve reflex activation and counterregulatory mechanisms codetermine the antihypertensive result of the individual. Chronic monotherapy with calcium antagonists results in an antihypertensive response that is related directly to the patient's age and pretreatment blood pressure and indirectly to renin. These studies led to a new treatment concept: calcium antagonists can be used as alternatives to diuretic drugs primarily in the older and low-renin patients and beta-blockers or converting enzyme inhibitors can be used in the younger or high-renin patients with greater efficacy. With the appropriate choice, calcium antagonists alone or combined with any other antihypertensive drug provide good blood pressure control with little subjective and objective adverse effects.