Quinapril hydrochloride is the newest member of a family of
angiotensin-converting enzyme (
ACE) inhibitors. On completion of laboratory and animal studies, a clinical program was initiated to evaluate the
antihypertensive and other properties of the
drug in human subjects. The initial phase of clinical development was concerned with the pharmacokinetics and pharmacology of
quinapril. The latter studies established a dose range for the
drug and explored its effect on human hemodynamics and blood pressure. Safety and interactions with other drugs were also examined. Subsequent studies explored the safety and efficacy of
quinapril in patients with mild to moderate
hypertension and, later, in patients with more severe
hypertension. Results of these studies supported the recommendation of a once daily dosage of
quinapril, 10-40 mg, as first-line
therapy in the management of
hypertension, with
diuretics as concomitant
therapy as required in patients with severe
hypertension.
Quinapril has also been found to be the most potent of all available
ACE inhibitors in binding to tissue ACE, which may contribute to its potent and sustained duration of action. Clinical evaluation of
quinapril has also been undertaken in patients with
congestive heart failure. Initial findings indicate that doses of 10-20 mg/day, given twice daily, are therapeutic when administered with
diuretic or digitalis. Safety of the
drug has been established in 2700 patients.