Acute cardiovascular effects of the concurrent administration of enalapril, prazosin or amlodipine in healthy Nigerians

A. A. Ajayi, Mukaila Raji

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The acute circulatory effects of the combination of prazosin 1 mg, enalapril 10 mg or amlodipine 5 mg were evaluated and compared in placebo controlled, randomised, double blind, latin-square, cross-over study in 8 normotensive healthy Nigerians. Supine and erect blood pressure were reduced by the active treatment combinations (F = 8.8, P = 0.0006, analysis of variance). In all, the onset of blood pressure fall was within 2 h, with a peak reduction at 4-6 h and persisting for at least 12 h. The combination of converting enzyme inhibitor and alpha blocker, however, caused a significantly greater hypotensive action than the other combinations (P < 0.05, analysis of variance). There was a modest reflex tachycardia in the erect position on all treatments (P = 0.008). Cardiac autonomic reflexes or left ventricular echocardiographic indices were unaffected by the drug combinations. The haemodynamic effect of enalapril plus prazosin combination, which separately cause little hypotensive effect in Africans, may reflect an important pharmacodynamic interaction between α1 and angiotensin II vascular receptors. All combinations lower blood pressure and warrant further study in Nigerian hypertensives. However, the enalapril plus prazosin combination caused the greatest blood pressure fall, and caution is indicated during their concurrent use, owing to enhanced first dose hypotension.

Original languageEnglish (US)
Pages (from-to)79-84
Number of pages6
JournalInternational Journal of Cardiology
Volume44
Issue number1
DOIs
StatePublished - Mar 15 1994
Externally publishedYes

Fingerprint

Amlodipine
Enalapril
Prazosin
Blood Pressure
Reflex
Analysis of Variance
Angiotensin Receptors
Enzyme Inhibitors
Drug Combinations
Tachycardia
Hypotension
Cross-Over Studies
Blood Vessels
Hemodynamics
Placebos
Therapeutics

Keywords

  • Amlodipine
  • Blood pressure
  • Combination
  • Enalapril
  • Nigerian volunteers
  • Prazosin
  • α-Angiotensin II interaction

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

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title = "Acute cardiovascular effects of the concurrent administration of enalapril, prazosin or amlodipine in healthy Nigerians",
abstract = "The acute circulatory effects of the combination of prazosin 1 mg, enalapril 10 mg or amlodipine 5 mg were evaluated and compared in placebo controlled, randomised, double blind, latin-square, cross-over study in 8 normotensive healthy Nigerians. Supine and erect blood pressure were reduced by the active treatment combinations (F = 8.8, P = 0.0006, analysis of variance). In all, the onset of blood pressure fall was within 2 h, with a peak reduction at 4-6 h and persisting for at least 12 h. The combination of converting enzyme inhibitor and alpha blocker, however, caused a significantly greater hypotensive action than the other combinations (P < 0.05, analysis of variance). There was a modest reflex tachycardia in the erect position on all treatments (P = 0.008). Cardiac autonomic reflexes or left ventricular echocardiographic indices were unaffected by the drug combinations. The haemodynamic effect of enalapril plus prazosin combination, which separately cause little hypotensive effect in Africans, may reflect an important pharmacodynamic interaction between α1 and angiotensin II vascular receptors. All combinations lower blood pressure and warrant further study in Nigerian hypertensives. However, the enalapril plus prazosin combination caused the greatest blood pressure fall, and caution is indicated during their concurrent use, owing to enhanced first dose hypotension.",
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