title: The effects of the calcium antagonist amlodipine on blood pressure and platelet aggregation in hypertensive patients.
abstract: This study examined the antihypertensive efficacy of open-label amlodipine in once-daily doses of 5-10 mg for 12 weeks. Efficacy was assessed by measurement of blood pressure and heart rate in the supine, seated and standing positions and after exercise periodically during the study. Blood pressure was significantly reduced throughout the study with no change in heart rate. During a placebo-washout phase after the 12-week active treatment phase of the study, blood pressure returned to baseline values. After the 4-week placebo-washout phase some patients received a single 10-mg dose of amlodipine followed by an exercise test 6 h later, which showed that amlodipine lowered blood pressure without blunting the normal physiological response to exercise. In these patients amlodipine also significantly reduced ex vivo platelet aggregation induced by collagen or ADP.
authors.affiliation: Clinical Pharmacology Unit, School of Medicine, Universidad Centro Occidental Lisandro Alvarado, Barquisimeto, Venezuela.
authors.forename: R
authors.initials: R
authors.lastname: Hernández
authors.forename: A R
authors.initials: AR
authors.lastname: Carvajal
authors.forename: M J
authors.initials: MJ
authors.lastname: Armas-de Hernández
authors.forename: J
authors.initials: J
authors.lastname: Guerrero-Pajuelo
authors.forename: M C
authors.initials: MC
authors.lastname: Armas-Padilla
authors.forename: O
authors.initials: O
authors.lastname: Barragán
authors.forename: I
authors.initials: I
authors.lastname: Machado-de Alvarado
mesh_terms: D017311:Amlodipine; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology*; D004334:Drug Administration Schedule; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D010975:Platelet Aggregation Inhibitors; D017311:Amlodipine; D009543:Nifedipine