PO (Adults): Immediate-release tablets —5 mg 2–3 times daily (not to exceed 5 mg 4 times daily) (may start with 2.5 mg 2–3 times daily in elderly). Extended-release tablets —5–10 mg once daily; may increase, as needed, (in 5-mg increments) up to maximum dose of 30 mg/day.
PO (Children >5 yr): Immediate-release tablets5 mg 2–3 times daily (not to exceed 15 mg/day). Extended-release tablets (children greater or equal to 6 yr)-5 mg once daily; may , as needed, (in 5-mg increments) up to maximum dose of 20 mg/day.
Transdermal (Adults): One 3.9 mg system applied twice week-ly (every 3–4 days).
Absorption: Rapidly absorbed following oral administration, but undergoes extensive first-pass metabolism; XL tablets provide extended release. Transdermal absorption occurs by passive diffusion through intact skin and bypasses the first-pass effect.
Distribution: Widely distributed.
Metabolism/Excretion: Extensively metabolized by the liver (CYP3A4 enzyme system); one metabolite is pharmacologically active; metabolites are renally excreted with negligible (<0.1%) excretion of unchanged drug.