Effect of age on the pharmacokinetics of ranitidine in healthy Mexican volunteers

Numerous reports in the literature have demonstrated changes in drug pharmacokinetics that result with age. Ranitidine is a drug commonly used in Mexico. However no reports on the pharmacokinetics of ranitidine in the Mexican population are available in the literature. The objective of this clinical trial was to evaluate the effect of age on the pharmacokinetics of ranitidine in healthy Mexican volunteers. Methods: Twenty-one healthy Mexican volunteers were included, who were divided into three groups G1 (18-30 y), G2 (31-50 y) and G3 (51-60 y). The volunteers were given a single oral dose of 300 mg of ranitidine and blood samples were obtained, and some pharmacokinetic parameters were correlated with age. Results: Statistically significant differences were noted in the distribution volume (4.00 ± 1.11 L/kg in G1, vs 2.15 ± 1.12 L/kg in G3) of the drug. Clearance was faster among the G1 (1.11±0.12 mL/hr) group compared to the G3 group (0.58 ± 0.19 mL/hr). Differences for AUC, t1/2 and Cmax are more evident between G1 and G3. Discussion: The results of our study indicated that in patients over 50 years of age who are treated with ranitidine, the dosage of this agent should be appropriately adjusted in order to avoid adverse effects that may develop with prolonged use of the drug. However it is very important to consider that our result only reflect observations made from a single dose study, thus it is necessary to carry out study under chronic dosage treatment.