Knapp Lloyd E.; Frank, Graham J.; McLain, Richard; Rieger, Maira M.; Posvar, Edward; Singer, RobertJournal of Cardiovascular Pharmacology: 1990 Article: PDF Only Free Abstract Summary Quinapril, a new angiotensin-converting enzyme (ACE) inhibitor with an intermediate duration of action, has been extensively studied in patients with hypertension and congestive heart failure (CHF) during a worldwide clinical development program. A comprehensive safety data base was established to allow appropriate analyses of the extensive patient safety data. The safety of quinapril has been evaluated in 2,697 patients with hypertension and CHF, including 451 elderly patients (≥65 years), and has been compared with safety data from a total of 1,058 patients receiving a comparative therapy. A comparison of the double-blind studies demonstrated that quinapril has a lower incidence of adverse events and/or withdrawals than reported for captopril or enalapril. An analysis of the onset of adverse events did not show either an increase with time on quinapril therapy or a dose relationship. The proportion of patients who experienced orthostatic hypotension or hypotension was less than that of patients who were treated with captopril or enalapril. An analysis of all events (from both double-blind and long-term, open-label studies) showed no increase in the incidence of events reported in patients with CHF compared with hypertensive patients. When the data for all studies were combined, an age analysis showed no increase in the total reporting of adverse events in elderly patients compared with the younger patients studied. The incidence of adverse events was lower in those patients not receiving concomitant diuretic therapy. An overall analysis of clinical laboratory data indicated that quinapril did not have significant adverse effects on clinical laboratory parameters when compared with captopril, enalapril, or placebo. Quinapril had minimal adverse effects on renal function both in patients with normal renal function and in patients with pre-existing renal impairment. Quinapril has been extensively studied and has been shown in comparative clinical studies to be better tolerated than captopril and enalapril. Quinapril is equally well tolerated in the young and the elderly. © Lippincott-Raven Publishers.