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Pharmacokinetics and Pharmacodynamics of Oral and Intravenous Cimetidine in Seriously III Patients
Author(s) -
Sandborn William J.,
Forland Steven C.,
Cutler Ralph E.,
Strong Richard M.
Publication year - 1990
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 - 10.1002/j.1552-4604.1990.tb03622.x
Subject(s) - cimetidine , medicine , pharmacokinetics , dosing , bioavailability , oral administration , pharmacodynamics , anesthesia , pharmacology
This study was done to determine if the pharmacokinetics and gastric pH response of intravenous cimetidine are superior to oral dosing in seriously ill patients. A paired study of intravenous followed by oral liquid cimetidine was given to eight men and two women who were inpatients in a VA Hospital. Treatment was prescribed for either upper gastrointestinal (GI) bleeding or prophylaxis against GI bleeding. All patients received cimetidine 300 mg every 6 hours intravenously on day 1 and orally on day 2. After the fourth dose each day, venous blood samples and gastric pH measurements were taken serially for 6 hours. Peak serum cimetidine concentration was 2.0 ± 0.5 mg/L for the intravenous dose and 1.5 ± 0.3 mg/L for the oral dose ( P = .001). Area under the curve (AUC) of cimetidine concentration was 3.81 ± 1.1 mg/hr/L for the intravenous dose and 4.19 ± 1.22 mg/hr/L for the oral dose ( P > .30). Bioavailability (AUC po /AUC iv ) was 1.13 ± 0.25, demonstrating complete oral absorption. The time during a 6‐hour dosing interval that the gastric pH remained above 3.0 was 3.3 ± 2.1 hours for the intravenous dose and 2.5 ± 2.3 hours for the oral dose, P = .171). The time that the serum cimetidine concentration remained above 0.5 mg/L was 2.0 ± 0.9 hours for the intravenous dose and 2.7 ± 1.0 hours for the oral dose ( P = .055). We concluded that bioavailability, time that gastric pH is maintained >3.0, and time that the serum cimetidine concentration is >0.5 mg/L for intravenous cimetidine are not significantly different from oral cimetidine in seriously ill patients.