Chlorpromazine is an anti-psychotic medication in a group of drugs called phenothiazines (FEEN-oh-THYE-a-zeens). It works by changing the actions of chemicals in your brain.
Chlorpromazine is used to treat psychotic disorders such as schizophrenia or manic-depression, and severe behavioral problems in children. It is also used to treat nausea and vomiting, anxiety before surgery, chronic hiccups, acute intermittent porphyria, and symptoms of tetanus.

Usual Adult Dose for Psychosis:

IM: Initial Dose 25 to 50 mg. The dose may be repeated in one hour. Subsequent doses may be increased and given every 2 to 4 hours as needed.
Oral: Initial Dose: 10 to 25 mg orally 3 times a day. Total daily doses should be increased in 20 to 50 mg increments every 3 or 4 days until symptoms are controlled.

Usual Maintenance Dose: 200 mg/day orally :

Some patients require higher dosages (e.g., 800 mg daily is not uncommon in discharged mental patients). Increase dosage gradually until symptoms are controlled. Maximum improvement may not be seen for weeks or even months. Continue optimum dosage for 2 weeks, then gradually reduce dosage to the lowest effective maintenance level.