A clinical pharmacological assessment of doxazosin and enalapril in combination.
This study in 12 normotensive males investigated potential pharmacokinetic and pharmacodynamic interaction mechanisms resulting from the combination of enalapril and doxazosin. Blood pressure reductions were consistently greater with the combination but there was no evidence of a significant pharmacodynamic interaction (as determined by heart rate changes, renal function tests or by pressor responsiveness indices) and there was no evidence of a pharmacokinetic interaction with either drug. Responsiveness to each drug i.e. blood pressure reduction per unit drug concentration was not significantly altered in the combination regimen. In conclusion, these results suggest that the combination of enalapril and doxazosin produces a usefully additive hypotensive effect but there was no evidence of synergism i.e an effect which was more than additive.
Bainbridge
A D
AD
Department of Medicine and Therapeutics, Gardiner Institute, Western Infirmary, Glasgow, G11 6NT, Scotland.
Meredith
P A
PA
Elliott
H L
HL
D000328:Adult; D000959:Antihypertensive Agents / Q000493:pharmacokinetics / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D017292:Doxazosin / Q000493:pharmacokinetics / Q000494:pharmacology; D004338:Drug Combinations; D004347:Drug Interactions; D004656:Enalapril / Q000493:pharmacokinetics / Q000494:pharmacology; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D011311:Pressoreceptors; D017596:Renal Plasma Flow, Effective / Q000187:drug effects
D000959:Antihypertensive Agents; D004338:Drug Combinations; D004656:Enalapril; D017292:Doxazosin