Pharmacodynamics
Chlorprothixene blocks postsynaptic dopaminergic D1 and D2 receptors and, with weaker affinity, serotonin histamine and adrenergic receptors, in the brain. Thus it has sedative, antipsychotic and antidepressant effects. Furthermore, it suppresses the release of hypothalamic and pituitary hormones and is thought to suppress the reticular activating system, thereby affecting basal metabolic rate, body temperature, wakefulness, vasomotor tone, and vomiting.
Pharmacokinetics
The half-life is approximately 8 hours.
Drug Interactions
- Chlorprothixene may increase plasma levels of concomitantly administered lithium.
- When chlorprothixene is administered concomitantly with opioids, the opioid dose should be reduced (by approximately 50%) because chlorprothixene significantly potentiates the therapeutic effects and side effects of opioids.
- The concomitant use of chlorprothixene and tramadol should be avoided. Seizures may occur with this combination.
- Additive sedative effects and confusional states are to be expected when chlorprothixene is given together with benzodiazepines or barbiturates.
- Particular caution should be exercised when chlorprothixene is combined with other anticholinergic drugs (tricyclic antidepressants and antiparkinsonian agents): delirium, high fever, severe constipation up to ileus and glaucoma may occur, especially in the elderly.
