Imodium Pharmacology, Pharmacokinetics, Studies, Metabolism - Loperamide

Imodium Pharmacology, Pharmacokinetics, Studies, Metabolism - Loperamide

CLINICAL PHARMACOLOGY

In vitro and animal studies show that loperamide hydrochloride acts by slowing intestinal motility and by affecting water and electrolyte movement through the bowel. Loperamide inhibits peristaltic activity by a direct effect on the circular and longitudinal muscles of the intestinal wall.

In man, loperamide prolongs the transit time of the intestinal contents. It reduces the daily fecal volume, increases the viscosity and bulk density, and diminishes the loss of fluid and electrolytes. Tolerance to the antidiarrheal effect has not been observed.

Clinical studies have indicated that the apparent elimination half-life of loperamide hydrochloride in man is 10.8 hours with a range of 9.1 - 14.4 hours. Plasma levels of unchanged drug remain below 2 nanograms per mL after the intake of a 2 mg capsule of loperamide hydrochloride. Plasma levels are highest approximately five hours after administration of the capsule and 2.5 hours after the liquid. The peak plasma levels of loperamide were similar for both formulations. Of the total excreted in urine and feces, most of the administered drug was excreted in feces. In those patients in whom biochemical and hematological parameters were monitored during clinical trials, no trends toward abnormality during loperamide hydrochloride therapy were noted. Similarly, urinalyses, EKG and clinical ophthalmological examinations did not show trends toward abnormality.