Promethazine-How does it act in nausea and vomiting?

Promethazine is an Antiemetic prescribed for nausea and vomiting. Antiemetics treat motion sickness, chemotherapy-induced nausea and vomiting, and the side effects of general anesthetics and opioid analgesics

Few medicines act on the chemoreceptor trigger zone-CTZ (in the brain) by preventing the stimulation. The chemoreceptor trigger zone is a vomiting center. Some medications act as prokinetic agents by speeding up the rate at which the stomach empties.

Parameters	Description
Category of Drug	Phenothiazine derivative
Mechanism of Action	Promethazine is a direct antagonist at the mesolimbic dopamine receptors and alpha-adrenergic receptors in the brain.
Structure 1
IUPAC name 1	N,N-dimethyl-1-phenothiazin-10-ylpropan-2-amine
Molecular details 1	Formula- C17H20N2S Molecular weight- 284.4 g/mol
Indications	Promethazine-Antiemetics is used for 1. Nausea 2. Vomiting 3. Labyrinthine disorders 4. Moon sickness 5. Premedication 6. Allergic rhinitis 7. Vasomotor rhinitis
Well Known Pharmaceutical Brands	Avomine- Abbott
Available dosage forms	1. TABLETS 2. SYRUP 3. INJECTION
Dose	Nausea and vomiting (including postoperative): 12.5 to 25 mg, repeated at intervals of not less than 4 h
Contraindications	1. Porphyria 2. Hypersensitivity 3. Coma 4. Hypokalaemia
Precautions	1. Prostatic hypertrophy 2. Urinary retention 3. Glaucoma 4. Hepatic disease 5. Epilepsy 6. Elderly and children
Adverse Effects	1. Drowsiness 2. Dizziness 3. Sedation 4. Headache 5. Psychomotor impairment 6. Urinary retention 7. Dry mouth 8. Blurred vision 9. Gastrointestinal disturbances 10. Hypersensitivity reactions 11. Photosensitivity reactions 12. Jaundice 13. Blood disorders
Pregnancy Category	C

References

• National formulary
• drug profiles ^{2, 3, 4}