Rapidly absorbed from GI tract. Food increases absorption. Protein binding: 95%. Extensively metabolized in liver. Excreted in urine and feces. Unknown if removed by hemodialysis. Half-life: 25–41 hr.
Well absorbed after PO administration. Protein binding: 83%. Widely distributed in tissues; CNS concentration exceeds plasma concentration. Undergoes extensive first-pass metabolism in the liver. Primarily excreted in urine. Half-life: 6 hr.
Initially, 25 mg twice a day, then 25–50 mg 2–3 times a day on the second and third days, up to 300–400 mg/day in divided doses 2–3 times a day by the fourth day. Further adjustments of 25–50 mg twice a day may be made at intervals of 2 days or longer. Maintenance: 300–800 mg/day (adults); 50–200 mg/day (elderly).
Renal impairment, hepatic impairment, cardiovascular disease, thyroid disease, hyperprolactinemia, neuromalignant syndrome, tardive dyskinesia, seizure disorders, cataracts, dementia, suicide tendency, lactation; patients should be monitored for signs and symptoms of diabetes mellitus, severe CNS depression