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Effects of Concomitant Therapy with Diltiazem on the Lipid Responses to Simvastatin in Chinese Subjects
Author(s) -
You Joyce H. S.,
Chan Winnie K. Y.,
Chung Polly F. P.,
Hu Miao,
Tomlinson Brian
Publication year - 2010
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1177/0091270009358082
Subject(s) - diltiazem , simvastatin , medicine , crossover study , confidence interval , lipid profile , cholesterol , pharmacology , endocrinology , placebo , calcium , alternative medicine , pathology
Diltiazem increases systemic exposure to simvastatin via inhibition of CYP3A. This study assessed the impact of this interaction on the lipid‐lowering effects of simvastatin. Chinese patients with hypercholesterolemia were randomized to receive simvastatin 20 mg daily alone or together with diltiazem 60 mg 3 times daily for 4 weeks with a washout period of 4 weeks in an open‐label, crossover study. Blood pressure, fasting serum lipid profile, and safety tests were determined at baseline and after each treatment period. Trough serum diltiazem was measured at the end of the 4‐week combination treatment. In the 30 patients who completed the study, simvastatin treatment significantly reduced low‐density lipoprotein cholesterol by mean (± standard error) 41.0% ± 2.2% (P < .001), and the combination with diltiazem showed an additional reduction of 1.66% (95% confidence interval: −4.63 to 7.96, P > .05). The additional change in low‐density lipoprotein cholesterol with diltiazem showed a nonsignificant positive correlation with the trough serum diltiazem concentration (R 2 = 0.142, P = .058). Co‐administration of diltiazem 60 mg 3 times daily with simvastatin 20 mg daily tended to increase the changes in lipid parameters in these Chinese subjects, but the effects did not reach significance.