Adults

For pinworm: 100 mg chewable tablet as a single dose. May be repeated after 2-4 weeks if necessary. For roundworm, whipworm, and hookworm: 100 mg chewable tablet twice daily (morning and evening) for 3 consecutive days.

Elderly

No specific dosage adjustment is generally required for elderly patients, but caution is advised in those with significant hepatic impairment.

Renal_impairment

No dosage adjustment is considered necessary for patients with renal impairment, as systemic absorption is minimal and renal excretion is not the primary route.

Onset

Clinical effects (worm expulsion) typically observed within 1-3 days, depending on the type of infection and dosage regimen.

Excretion

Primarily excreted in the feces as unchanged drug and metabolites. A small amount (<2%) is excreted in the urine.

Half life

Approximately 2.5 to 5.5 hours for the parent drug.

Absorption

Poorly absorbed from the gastrointestinal tract (less than 10% bioavailability). Absorption is slightly increased with a fatty meal.

Metabolism

Extensively metabolized in the liver, primarily to its hydroxylated metabolite (e.g., hydroxymebantrin), which has little to no anthelmintic activity.

Cimetidine

May increase plasma concentrations of mebantrin by inhibiting its metabolism, potentially leading to increased side effects.

Metronidazole

Concomitant use with metronidazole has been associated with an increased risk of Stevens-Johnson syndrome/toxic epidermal necrolysis; concurrent use should generally be avoided.