Phenothiazine

These are also dopamine receptor antagonists.


Mechanism of action:
It is thought to affect the chemoreceptor trigger zone causing the blockage of dopamine receptors in the chemoreceptor trigger zone. It causes the inhibition of apomorphine induced vomiting.

Therapeutic uses:
It is effective in the treatment of nausea and vomiting which may be post operative or due to toxins or chemicals. It can be used in the treatment of acute migraine attacks and nausea and vomiting coming after the attacks.

It is also used as an antipsychotic drug.

Administration and dosage:
It can be administered orally or parenterally. The usual dosage of prochlorperazine is about 5 or 10 mg, 3-4 times daily.

Pharmacokinetics:
The onset of action of prochlorperazine is 30-45 minutes. The duration of action of prochlorperazine tablets is about 2.5-4.5 hours.

Adverse effects:
It may cause extrapyramidal reactions, tardive dyskinesia, hypotension and drowsiness.