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Effects of cimetidine on caffeine disposition in smokers and nonsmokers
Author(s) -
May David C,
Jarboe Charles H,
VanBakel Adrian B,
Williams Walter M
Publication year - 1982
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1982.91
Subject(s) - cimetidine , caffeine , cmax , volume of distribution , chemistry , oral administration , pharmacokinetics , absorption (acoustics) , medicine , endocrinology , physics , acoustics
The absorption, distribution, and elimination of caffeine, 2 mg/kg by mouth, were evaluated in six smokers and six nonsmokers before and on the fourth day of administration of cimetidine, 300 mg by mouth every 6 hr. Caffeine absorption, assessed by the maximal serum caffeine concentration (C max ) and the time to reach C max (t max ), was very rapid relative to elimination. The total body clearance (TBC) of caffeine was higher (2.49 ± 0.35 and 1.59 ± 0.19 ml/kg/min, P < 0.05) and the elimination half‐life (t½) shorter (190 ± 15 and 276 ± 30 min, P < 0.05) in smokers than nonsmokers, but C max , t max , and the apparent volume of distribution (Vd, app) did not differ (P > 0.05). Cimetidine decreased the TBC of caffeine by 31% (to 1.73 ± 0.28 ml/kg/min, P < 0.05) and by 42% (to 0.92 ± 0.11 ml/kg/min, P < 0.01) in smokers and nonsmokers. The increases in t½ were 45% (to 276 ± 25 min, P < 0.05) and 96% (to 542 ± 123 min, P < 0.05). C max , t max , and Vd, app were unaffected by cimetidine. Caffeine induced similar slight increases in blood pressure and pulse rate in smokers and nonsmokers both before and during cimetidine dosing. Clinical Pharmacology and Therapeutics (1982) 31, 656–661; doi: 10.1038/clpt.1982.91