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Pharmacokinetics and Pharmacodynamics of Famotidine in Children
Author(s) -
James Laura P.,
Marshall James D.,
Heulitt Mark J.,
Wells Thomas G.,
Letzig Lynda,
Kearns Gregory L.
Publication year - 1996
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.1552-4604.1996.tb04151.x
Subject(s) - famotidine , pharmacokinetics , pharmacodynamics , cmax , volume of distribution , urine , medicine , population , pharmacology , environmental health
The pharmacokinetics and pharmacodynamics of intravenous famotidine were studied in 12 children (1.1–12.9 years of age; mean weight ± standard deviation = 27.6 ± 21.2 kg) who were given the drug for prophylactic management of stress ulceration. After a 0.5‐mg/kg infusion of famotidine, timed blood (n = 10) and urine (n = 6) samples and repeated evaluations of intragastric pH (n = 13) were obtained from each subject. Pharmacokinetic parameters were determined from curve fitting of serum concentration data. The mean (± SD) maximum serum concentration (C max ) was 527.6 ± 281.2 ng/mL, the elimination half‐life (t 1/2 ) was 3.2 ± 3.0 hours, and the apparent steady‐state volume of distribution (Vd ss ) was 2.4 ± 1.7 L/kg. Plasma clearance (Cl) and renal clearance (Cl R ) were 0.70 ± 0.34 L/hr/kg and 0.43 ± 0.24 L/hr/kg, respectively. Over 24 hours, 73.0 ± 27.3% of the dose was excreted unchanged in the urine (F el ). Pharmacodynamic analysis of gastric pH data using the sigmoid E max model predicted that 50% of the maximal effect of famotidine (EC 50 ) occurs at a serum concentration of 26.0 ± 13.2 ng/mL. Children who did not have an initial intragastric pH ≤4 did not have a significant response in pH after receiving famotidine. Although Vd ss and Cl were higher in these children than those seen in adults, statistically significant relationships between these parameters and age were not observed in the study population. The pharmacodynamics and pharmacokinetics of famotidine in children older than one year of age appear to be similar to those noted in adults.