Prochlorperazine is a potent phenothiazine antipsychotic, derivative of the piperazine group, now largely used as an antiemetic and to treat vertigo. The effects of this drug is apparent at all levels of the nervous system. It antagonizes postsynaptic dopamine D1 receptor that activates adenylate cyclase and synthesis of cAMP. It also antagonizes D2 receptors which do not activate adenylate cyclase. It also inhinits pre- and post synaptic adrenoreceptors and also acetylcholine, serotonin and histamine receptors. These various pharacodynamic actions combine to produce not only antipsychotic, but also central antiemetic and sedative effects.
Children (not recommended in children <10 kg or <2 years): 10-14 kg: 2.5 mg every 12-24 hours as needed; maximum: 7.5 mg/day 15-18 kg: 2.5 mg every 8-12 hours as needed; maximum: 10 mg/day 19-39 kg: 2.5 mg every 8 hours or 5 mg every 12 hours as needed; maximum: 15 mg/day Adults: 5-10 mg 3-4 times/day; usual maximum:40 mg/day Antipsychotic: Children 2-12 years (not recommended in children <10 kg or <2 years): 2.5 mg 2-3 times/day; increase dosage as needed to maximum daily dose of 20 mg for 2-5 years and 25 mg for 6-12 years Adults: 5-10 mg 3-4 times/day; doses up to 150 mg/day may be required in some patients for treatment of severe disturbances Nonpsychotic anxiety: Adults: Usual dose: 15-20 mg/day in divided doses; do not give doses >20 mg/day or for longer than 12 weeks
Elderly: Initial: 2.5-5 mg 1 -2 times/day; increase dose at 4 to 7 day intervals by 2.5-5 mg/day; increase dosing intervals (twice daily, thrice daily, etc) as necessary to control response or side effects; maximum daily dose should probably not exceed 75 mg in elderly; gradual increases (titration) may prevent some side effects or decrease their severity. Prochlorperazine may be administered without regards of meal.