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Pharmacokinetic studies of cimetidine hydrochloride in adult horses
Author(s) -
SMYTH G. B.,
DURAN S.,
RAVIS W.,
CLARK C. R.
Publication year - 1990
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1990.tb04206.x
Subject(s) - cimetidine , pharmacokinetics , volume of distribution , chemistry , absorption (acoustics) , histamine h2 receptor , gastric acid , histamine , oral administration , liter , antagonist , pharmacology , medicine , stomach , receptor , biochemistry , physics , acoustics
Summary Histamine type II (H 2 ) antagonists inhibit gastric acid secretion and are useful in treating gastric and duodenal ulcer disease. To provide some information on the pharmacokinetics of the H 2 antagonist cimetidine, adult horses were given 3.3 mg/kg cimetidine intravenously (iv) or 3.3 and 10 mg/kg orally. Plasma cimetidine concentrations after 3.3 mg/kg orally were too low to measure. Following 33 mg/kg iv, cimetidine displayed two‐compartment characteristics with a t 1/2 of 0.083±0.039 h and t 1/2 of 2.23±0.64 h. The total body clearance was 0.443±0.160 litre/h/kg and the mean residence time was 2.74±1.11 h. This clearance and t 1/2 are similar to that in man. The volume of distribution (V SS ) and volume of the central compartment (V C ) were 1.138±0.230 and 0.276±0.102 litre/kg, respectively. After a single oral dose of 10 mg/kg as crushed tablets, peak plasma concentration of 1.81±0.82 μg/ml occurred at approximately 1.4 h. Oral absorption of cimetidine appeared variable and slow with an extent of absorption of 0.296±0.183 and a mean residence time for absorption of 1.99±0.79 h. This was less than in man. Based on a desired average steady state plasma concentration of 1.0 μg/ml, 11.0 mg/kg/day iv and 48 mg/kg/day orally can be recommended in adult horses.