indication

For as adjunctive therapy in the management of diarrhea

pharmacology

Diphenoxylate, an antidiarrheal, is effective as adjunctive therapy in the management of diarrhea. Diphenoxylate is rapidly and extensively metabolized in man by ester hydrolysis to diphenoxylic acid (difenoxine), which is biologically active and the major metabolite in the blood.

mechanism of action

Diphenoxylate is an opiate receptor agonists that stimulate mu receptors in GI to decrease the peristalsis and constrict the sphincters. Diphenoxylate has a direct effect on circular smooth muscle of the bowel, that conceivably results in segmentation and prolongation of gastrointestinal transit time. The clinical antidiarrheal action of diphenoxylate may thus be a consequence of enhanced segmentation that allows increased contact of the intraluminal contents with the intestinal mucosa.

toxicity

Coma, dry skin and mucous membranes, enlarged pupils of the eyes, extremely high body temperature, flushing, involuntary eyeball movement, lower than normal muscle tone, pinpoint pupils, rapid heartbeat, restlessness, sluggishness, suppressed breathing

biotransformation

Hepatic

absorption

90%

half life

12-14 hours

drug interactions

Donepezil: Possible antagonism of action

Galantamine: Possible antagonism of action