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.

Category of DrugPhenothiazine derivative
Mechanism of ActionPromethazine is a direct antagonist at the mesolimbic dopamine receptors and alpha-adrenergic receptors in the brain.
Structure 1Promethazine.png
IUPAC name 1N,N-dimethyl-1-phenothiazin-10-ylpropan-2-amine
Molecular details 1Formula- C17H20N2S
Molecular weight- 284.4 g/mol
IndicationsPromethazine-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
Promethazine Syrup at Price 1 USD/Box in Rajkot | Harbhole Enterprise
DoseNausea and vomiting (including
postoperative): 12.5 to 25 mg, repeated at intervals of not less than 4 h
Contraindications1. 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


  • National formulary
  • drug profiles 2, 3, 4

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