Promethazine Hydrochloride is an Ethylamino derivative of Phenothiazine and first-generation antihistamine.
Mode of action:
Promethazine, a phenothiazine, is an H1-antagonist with anticholinergic, sedative, and antiemetic effects and some local anesthetic properties. Promethazine is used as an antiemetic or to prevent motion sickness. Like other H1-antagonists, Promethazine competes with free histamine for binding at H1-receptor sites in the GI tract, uterus, large blood vessels, and bronchial muscle. The relief of nausea appears to be related to central anticholinergic actions and may implicate activity on the medullary chemoreceptor trigger zone.
Promethazine Hydrochloride is well absorbed from the gastrointestinal tract. Following oral administration, peak plasma concentrations are achieved in 2 to 3 hours and effects usually last 4 to 6 hours. On average, 88% of a Promethazine dose is absorbed after oral administration; however, the absolute bioavailability is only 25% because of first-pass clearance. Protein binding is 93%.
Promethazine is widely distributed in body tissues and readily crosses the placenta. Overdoses may result in CNS depression or excitation.
Promethazine Hydrochloride is metabolized in the liver.
Route of elimination:
Promethazine Hydrochloride is metabolized in the liver, with the sulfoxides of Promethazine and N-desmethylpromethazine being the predominant metabolites appearing in the urine.
Dosage and Administration:
Animals: 1 bolus per 75kg body weight orally once daily.
Or, According to the prescription of the registered Veterinarian.
Thazine bolus is contra indicated for animals who have exhibited hypersensitivity to this drug or other Phenothiazine derivatives.
Symptoms of overdose include mild depression of the central nervous system and cardiovascular system to profound hypotension, respiratory depression, unconsciousness, and sudden death.