Chlorprothixene

A carbamate with hypnotic, sedative, and some muscle relaxant properties, although in therapeutic doses reduction of anxiety rather than a direct effect may be responsible for muscle relaxation. Chlorprothixene has been reported to have anticonvulsant actions against petit mal seizures, but not against grand mal seizures (which may be exacerbated). It is used in the treatment of anxiety disorders, and also for the short-term management of insomnia but has largely been superseded by the benzodiazepines. (From Martindale, The Extra Pharmacopoeia, 30th ed, p603) Chlorprothixene is a controlled substance in the U.S.

Oral

Psychoses

Adult: 15-50 mg 3-4 times daily increased according to response for up to 600 mg or more daily in severe or resistant conditions.

Elderly: Dose reduction may be needed.

Intramuscular

Psychoses

Adult: 25-100 mg up to 4 times daily.

Elderly: Dose reduction may be needed.

Oral

Psychoses

Adult: 15-50 mg 3-4 times daily increased according to response for up to 600 mg or more daily in severe or resistant conditions.

Elderly: Dose reduction may be needed.

Intramuscular

Psychoses

Adult: 25-100 mg up to 4 times daily.

Elderly: Dose reduction may be needed.

Contraindications include alcohol abuse (adds to the central nervous system (CNS) depressant effects), blood disease, enlarged prostate, glaucoma, heart or blood vessel disease, lung disease, Parkinsons disease, stomach ulcers, urination problems (thioxanthenes may worsen the condition), liver disease (higher blood levels of thioxanthenes may occur, increasing the likelihood of side effects), Reyes syndrome (the risk of liver problems may be increased), and seizure disorders (the risk of seizures may be increased).

Chlorprothixene may increase the plasma-level of concomitantly given lithium. In order to avoid lithium intoxication, lithium plasma levels should be monitored closely. If Chlorprothixene is given concomitantly with opioids, the opioid dose should be reduced (by approx. 50%), because Chlorprothixene amplifies the therapeutic actions and side-effects of opioids massively. Avoid the concomitant use of Chlorprothixene and tramadol (Ultram). Massive seizures may be encountered with this combination. Consider additive sedative effects and confusional states to emerge, if Chlorprothixene is given with benzodiazepines or barbituates. Choose particular low doses of these drugs. Exert particular caution in combining Chlorprothixene with other anticholinergic drugs (tricyclic antidepressants and antiparkinsonian agents): Particularly the elderly may develop delirium, high fever, severe obstipation, even ileus and glaucoma.

Dry mouth, constipation, urinary retention, mydriasis; agitation, insomnia, depression, convulsions, nasal congestion, tachycardia, postural hypotension, blurred vision, inhibition of ejaculation; urticaria, exfoliative dermatitis; agranulocytosis; extrapyramidal dysfunction; altered endocrine and metabolic functions.