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Alpha-adrenergic blockade makes minimal contribution to ketanserin's hypotensive effect
T C Naslund1, W J Merrell, J H Nadeau
1Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232.
Clinical Pharmacology and Therapeutics
|December 1, 1988
Summary
Ketanserin lowers blood pressure similarly to prazosin, but with significantly less alpha-adrenergic blockade. This suggests ketanserin
Area of Science:
- Pharmacology
- Cardiovascular Medicine
Background:
- Ketanserin is a selective serotonin (S2) receptor antagonist investigated for hypertension.
- Its antihypertensive mechanism may involve alpha-adrenergic antagonism.
Purpose of the Study:
- To determine the contribution of alpha-adrenergic blockade to ketanserin's hypotensive effects.
- To compare ketanserin's alpha-blockade with prazosin, a known alpha 1-adrenergic antagonist.
Main Methods:
- Six hypertensive patients received placebo, ketanserin (40 mg q8h), and prazosin (5 mg q8h) in a randomized, crossover design.
- Blood pressure was monitored, and alpha-adrenergic blockade was assessed by phenylephrine infusion challenge.
Main Results:
- Both ketanserin and prazosin significantly lowered blood pressure comparably.
- Alpha-adrenergic blockade was evident with both drugs, but significantly less pronounced with ketanserin (dose ratio 1.69) compared to prazosin (dose ratio 7.38).
Conclusions:
- Ketanserin exhibits significant antihypertensive effects.
- Mechanisms beyond alpha-adrenergic blockade likely contribute to ketanserin's blood pressure-lowering action.