title: Platelet function during antihypertensive treatment with quinapril, a novel angiotensin converting enzyme inhibitor.
abstract: The effect of various antihypertensive medications on platelet function is of increasing interest. Conflicting effects of captopril on platelet function are reported and the impact of angiotensin converting enzyme (ACE) inhibitors not containing a sulfhydryl group such as enalapril, lisinopril, and quinapril on platelet function remains unstudied. Therefore, the aim of the present study was to examine the effect of antihypertensive treatment with quinapril, a novel ACE inhibitor not containing a sulfhydryl group, on platelet function. Ten white men (age range of 32-61 years) with untreated mild-to-moderate essential hypertension (supine diastolic blood pressure greater than 95 mm Hg) were treated with 4 weeks each of placebo and quinapril in a double-blind, randomized, crossover design. Quinapril (20 mg twice a day) significantly lowered systolic (p less than 0.01) and diastolic blood pressure (p less than 0.01) without any significant effect on heart rate or plasma catecholamines. No significant change was noted for in vitro platelet aggregation induced by epinephrine, ADP, or collagen. Plasma concentrations of the platelet release factors beta-thromboglobulin and platelet factor 4 did not change, nor did the platelet content of norepinephrine, platelet weight (mg/10 ml of blood), circulating platelet count, or platelet size. Thus, as assessed by a broad spectrum of platelet parameters, we found that antihypertensive treatment with quinapril has no significant effect on platelet function in patients with mild-to-moderate essential hypertension. These "platelet-neutral" properties of quinapril suggest that quinapril, both from a thromboembolic and a hemostatic point of view, may be a rather safe agent for treatment of hypertension.
authors.affiliation: Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor.
authors.forename: R K
authors.initials: RK
authors.lastname: Gupta
authors.forename: S E
authors.initials: SE
authors.lastname: Kjeldsen
authors.forename: E
authors.initials: E
authors.lastname: Motley
authors.forename: A B
authors.initials: AB
authors.lastname: Weder
authors.forename: A J
authors.initials: AJ
authors.lastname: Zweifler
authors.forename: S
authors.initials: S
authors.lastname: Julius
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000959:Antihypertensive Agents / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects; D003094:Collagen / Q000494:pharmacology; D004837:Epinephrine / Q000097:blood / Q000494:pharmacology; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000188:drug therapy*; D007546:Isoquinolines / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D010974:Platelet Aggregation / Q000187:drug effects; D010976:Platelet Count / Q000187:drug effects; D010978:Platelet Factor 4 / Q000378:metabolism; D000077583:Quinapril; D044005:Tetrahydroisoquinolines; D001620:beta-Thromboglobulin / Q000378:metabolism
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D007546:Isoquinolines; D044005:Tetrahydroisoquinolines; D001620:beta-Thromboglobulin; D010978:Platelet Factor 4; D000244:Adenosine Diphosphate; D003094:Collagen; D000077583:Quinapril; D009638:Norepinephrine; D004837:Epinephrine