Adult:
As hydrochloride: Initially, 3-9 mg bid, adjusted according to response. Elderly: Initial dose is reduced to 1/4 or 1/2 of the normal starting dose.
Oral
TREATMENT OF DEPRESSION
Adult:
Initially, 1 mg daily increased after 1 wk to 2 mg daily and then to a max of 3 mg daily, last dose should be given not later than 4 p.m. Doses >2 mg should be given in 2 divided doses. Discontinue treatment if there is no improvement within 1 wk of using the max dose.
Elderly: Initially, 0.5 mg daily increased after 1 wk to 1 mg daily with the last dose given not later than 4 p.m. Max: 2 mg daily in 2 divided doses.
Intramuscular
TREATMENT OF PSYCHOSES
Adult:
As decanoate: Initially, 20 mg (1 ml of a 2% oily solution) is given as test dose. After at least 7 days and depending on the response, subsequent doses of 20-40 mg may be given at intervals of 2-4 wk. Usual maintenance dose: 50 mg every 4 wk to 300 mg every 2 wk. Up to 400 mg wkly may be used in severe or resistant cases.
Elderly: Initial dose: ¼ or ½ of the usual initial dose.
Precautions
Patients with convulsive disorders; advanced hepatic, renal, CV or resp disease; tasks requiring mental alertness; elderly (especially with dementia), and debilitated patients; neuroleptics with sedative effect must be withdrawn gradually; history of angle-closure glaucoma; urinary retention; prostatic hyperplasia; breast cancer, prolactin dependent tumours; parkinsonism; myasthenia gravis; pregnancy; Avoid direct sunlight.
Potentially Life-threatening
Adverse Drug Reactions
Rigidity, tremors, restlessness, tardive dyskinesia, insomnia, dryness of mouth, wt gain, sexual dysfunction, galactorrhoea and menstrual disturbances.
Adverse Drug Reactions
Neuroleptic malignant syndrome (hyperthermia, hypertonicity of skeletal muscles, unconsciousness and autonomic nervous system instability).
Interactions
Potentiates CNS effects of alcohol, general anaesthetics, hypnotics, anxiolytics and opioids. Blocks antihypertensive effect of guanethidine.
May potentiate the adverse effects of drugs that have anti-muscarinic effects such as TCAs when used together. Reduced efficacy of levodopa. Increases adverse extrapyramidal symptoms with dopamine antagonists (metoclopramide and prochlorperazine).
