Ranitidine kinetics in chronic renal impairment

The effects of moderate to severe renal impairment on kinetics of the H 2 ‐blocker ranitidine were investigated in 16 patients divided into two groups. Mean inulin clearance (Cl In ) was 35 ± 18.3 ml/min/ 1.73 m 2 in group I and 7.4 ± 3.5 ml/min/1.73 m 2 in group II. Each patient received a single 150‐mg oral dose of ranitidine. Values determined were maximum plasma concentration (MC) and time of occurrence, AUC, elimination t½ (t½β), total amount of unchanged ranitidine recovered in urine, and ranitidine renal clearance (Cl R ). MC values were higher and longer delayed than values reported in subjects with normal renal function. The t½β was longer in group I and group II and correlated with the degree of renal impairment. The amount of ranitidine excreted within the first 24 hr decreased (18% of the dose in group I and 6% of the dose in group II), and Cl R correlated strongly with Cl In , indicating that the observed changes in ranitidine kinetics are mainly related to changes in its renal excretion. Clinical Pharmacology and Therapeutics (1983) 34, 667–672; doi: 10.1038/clpt.1983.230