A phenothiazine with actions similar to chlorpromazine but with less antipsychotic activity. It is primarily used in short-term treatment of disturbed behavior and as an antiemetic. [PubChem]
Indication
Used as an adjunct for short term treatment of moderate and severe psychomotor agitation. Also used to treat agitation or restlessness in the elderly.
Pharmacology
Promazine belongs to a group of medications known as the phenothiazine antipsychotics. It acts by blocking a variety of receptors in the brain, particularly dopamine receptors. Dopamine is involved in transmitting signals between brain cells. When there is an excess amount of dopamine in the brain it causes over-stimulation of dopamine receptors. These receptors normally act to modify behaviour and over-stimulation may result in psychotic illness. Promazine hydrochloride blocks these receptors and stops them becoming over-stimulated, thereby helping to control psychotic illness. Promazine has weak extrapyramidal and autonomic side effects which lead to its use in the elderly, for restless or psychotic patients. Its anti-psychotic effect is also weaker and it is not useful in general psychiatry.
Toxicity
Side effects include: extrapyramidal symptoms, drowsiness, weight gain, dry mouth, constipation, endocrine effects (such as gynaecomastia and menstrual disturbance), sensitivity to sunlight and haemolytic anaemia.
Affected Organisms
Humans and other mammals
Biotransformation
Hepatic, primarily to N-desmethylpromazine and promazine sulfoxide.
Absorption
Absorption may be erratic and peak plasma concentrations show large interindividual differences.
