DOSAGE AND ADMINISTRATION–ADULTS 1. To Control Severe Nausea and Vomiting: Adjust dosage to the response of the individual. Begin with the lowest recommended dosage. Oral Dosage–Tablets: Usually one 5 mg or 10 mg tablet 3 or 4 times daily. Daily dosages above 40 mg should be used only in resistant cases. Spansule capsules: Initially, usually one 15 mg capsule on arising or one 10 mg capsule q12h. Daily doses above 40 mg should be used only in resistant cases. 11 Rectal Dosage: 25 mg twice daily. I.M. Dosage: Initially 5 to 10 mg (1 to 2 mL) injected deeply into the upper outer quadrant of the buttock. If necessary, repeat every 3 or 4 hours. Total I.M. dosage should not exceed 40 mg per day. I.V. Dosage: 2½ to 10 mg (½ to 2 mL) by slow I.V. injection or infusion at a rate not to exceed 5 mg per minute. Compazine Injection may be administered either undiluted or diluted in isotonic solution. A single dose of the drug should not exceed 10 mg; total I.V. dosage should not exceed 40 mg per day. When administered I.V., do not use bolus injection. Hypotension is a possibility if the drug is given by I.V. injection or infusion. 2. Adult Surgery (for severe nausea and vomiting): Total parenteral dosage should not exceed 40 mg per day. Hypotension is a possibility if the drug is given by I.V. injection or infusion. I.M. Dosage: 5 to 10 mg (1 to 2 mL) 1 to 2 hours before induction of anesthesia (repeat once in 30 minutes, if necessary), or to control acute symptoms during and after surgery (repeat once if necessary). I.V. Dosage: 5 to 10 mg (1 to 2 mL) as a slow I.V. injection or infusion 15 to 30 minutes before induction of anesthesia, or to control acute symptoms during or after surgery. Repeat once if necessary. Compazine (prochlorperazine) may be administered either undiluted or diluted in isotonic solution, but a single dose of the drug should not exceed 10 mg. The rate of administration should not exceed 5 mg per minute. When administered I.V., do not use bolus injection. 3. In Adult Psychiatric Disorders: Adjust dosage to the response of the individual and according to the severity of the condition. Begin with the lowest recommended dose. Although response ordinarily is seen within a day or 2, longer treatment is usually required before maximal improvement is seen. Oral Dosage: Non-Psychotic Anxiety–Usual dosage is 5 mg 3 or 4 times daily; by Spansule capsule, usually one 15 mg capsule on arising or one 10 mg capsule q12h. Do not administer in doses of more than 20 mg per day or for longer than 12 weeks. Psychotic Disorders including Schizophrenia–In relatively mild conditions, as seen in private psychiatric practice or in outpatient clinics, dosage is 5 or 10 mg 3 or 4 times daily. In moderate to severe conditions, for hospitalized or adequately supervised patients, usual starting dosage is 10 mg 3 or 4 times daily. Increase dosage gradually until symptoms are controlled or side effects become bothersome. When dosage is increased by small increments every 2 or 3 days, side effects either do not occur or are easily controlled. Some patients respond satisfactorily on 50 to 75 mg daily. In more severe disturbances, optimum dosage is usually 100 to 150 mg daily. I.M. Dosage: For immediate control of adult schizophrenic patients with severe symptomatology, inject an initial dose of 10 to 20 mg (2 to 4 mL) deeply into the upper outer quadrant of the buttock. Many patients respond shortly after the first injection. If necessary, however, repeat the initial dose every 2 to 4 hours (or, in resistant cases, every hour) to gain control of the patient. More than three or four doses are seldom necessary. After control is achieved, switch patient to an oral form of the drug at the same dosage level or higher. If, in rare cases, parenteral therapy is needed for a prolonged period, give 10 to 20 mg (2 to 4 mL) every 4 to 6 hours. Pain and irritation at the site of injection have seldom occurred. Subcutaneous administration is not advisable because of local irritation.

We have studied the effects of prochlorperazine on the activities of UDP-glucuronosyltransferase and glucose-6-phosphatase (glucose-6-P'ase) in rat liver microsomes. The activity of UDP-glucuronosyltransferase was increased in a graded fashion by addition of prochlorperazine. Maximal stimulation occurred at 1 mg prochlorperazine to 2 mg microsomal protein, which resulted in a 6-fold increase in activity.