title: Effects of nifedipine on platelet function.
abstract: Effects of nifedipine on platelet aggregation were studied both in vitro and in vivo. From in vitro experiments, nifedipine inhibited platelet aggregation in a dose-dependent manner. The inhibition by nifedipine (final concentration 10 micrograms/ml) on epinephrine-induced and collagen-induced platelet aggregation was more than 90%, greater than that on adenosine diphosphate (ADP)-induced aggregation. The consumption ratio of small platelets (less than or equal to 6.4 fL) was higher than that of large platelets (greater than 6.4 fL), suggesting that nifedipine inhibits the aggregation of large platelets more effectively. Changes in the effects of nifedipine on platelet aggregation associated with exercise were also studied in six healthy volunteers. While platelet aggregability increased after exercise without administration of nifedipine, it was inhibited 90 minutes after the drug's administration (10 mg). The inhibition of collagen-induced and ADP-induced (2 microM) aggregation by nifedipine was particularly significant.
authors.forename: K
authors.initials: K
authors.lastname: Takahara
authors.forename: A
authors.initials: A
authors.lastname: Kuroiwa
authors.forename: T
authors.initials: T
authors.lastname: Matsushima
authors.forename: Y
authors.initials: Y
authors.lastname: Nakashima
authors.forename: M
authors.initials: M
authors.lastname: Takasugi
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D003094:Collagen / Q000494:pharmacology; D004837:Epinephrine / Q000097:blood / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009543:Nifedipine / Q000494:pharmacology*; D009638:Norepinephrine / Q000097:blood; D005082:Physical Exertion; D010974:Platelet Aggregation / Q000187:drug effects*; D010978:Platelet Factor 4 / Q000097:blood; D001620:beta-Thromboglobulin / Q000097:blood
chemical_list: D001620:beta-Thromboglobulin; D010978:Platelet Factor 4; D000244:Adenosine Diphosphate; D003094:Collagen; D009543:Nifedipine; D009638:Norepinephrine; D004837:Epinephrine