title: Impact of calcium antagonists on bleeding time in patients with chronic renal failure.
abstract: Haemorrhagic diathesis develops in chronic renal failure, in which calcium antagonists are used widely as antihypertensive agents. Although calcium antagonists are reported to impair platelet function, it has not been examined whether calcium antagonists alter bleeding time. The present study was conducted to clarify whether calcium antagonists affect bleeding time in chronic renal failure. Patients with chronic renal failure without and with calcium antagonists were enrolled (n = 156), and bleeding time (Ivy's method) as well as blood parameters (BUN, creatinine, platelet counts, and haemoglobin) were compared in patients with normal and prolonged bleeding time. Among patients not taking calcium antagonists (n = 34), three cases manifested prolonged bleeding time, whereas abnormal bleeding time was observed in 31 patients out of 122. Positive correlations were observed between bleeding time and BUN in both calcium antagonist-untreated (r = 0.46) and -treated groups (r = 0.25). The odds ratio for prolongation of bleeding time in patients taking calcium antagonists was 3.52 (95% CI, 1.01-12.33). In 12 calcium antagonist-treated patients with prolonged bleeding time, the withdrawal of calcium antagonists markedly shortened bleeding time (from 11.3 +/- 0.8 to 5.4 +/- 0.8 min, P < 0.05, n = 12). In contrast, in the additional group (n = 9), the continued treatment with calcium antagonists had no effect on bleeding time (from 11.7 +/- 0.9 to 10.0 +/- 1.0 min). Despite the inhibitory effect of calcium antagonists on bleeding time, no clinically serious events associated with haemorrhagic diathesis developed. In conclusion, calcium antagonists prolong bleeding time in patients with chronic renal failure. The subclinical (laboratory) effect of calcium antagonists however is not necessarily associated with haemorrhagic events of clinical significance.
authors.affiliation: Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan. khayashi@mc.med.keio.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Hayashi
authors.forename: H
authors.initials: H
authors.lastname: Matsuda
authors.forename: M
authors.initials: M
authors.lastname: Honda
authors.forename: Y
authors.initials: Y
authors.lastname: Ozawa
authors.forename: H
authors.initials: H
authors.lastname: Tokuyama
authors.forename: K
authors.initials: K
authors.lastname: Okubo
authors.forename: I
authors.initials: I
authors.lastname: Takamatsu
authors.forename: T
authors.initials: T
authors.lastname: Kanda
authors.forename: S
authors.initials: S
authors.lastname: Tatematsu
authors.forename: K
authors.initials: K
authors.lastname: Homma
authors.forename: T
authors.initials: T
authors.lastname: Saruta
mesh_terms: D000368:Aged; D001760:Bleeding Time; D001806:Blood Urea Nitrogen; D002121:Calcium Channel Blockers / Q000009:adverse effects*; D005260:Female; D006474:Hemorrhagic Disorders / Q000209:etiology; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000150:complications; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D010979:Platelet Function Tests
chemical_list: D002121:Calcium Channel Blockers