Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2016 Publisher: Rosemont Pharmaceuticals Ltd, Rosemont House, Yorkdale Industrial Park, Braithwaite Street, Leeds, LS11 9XE
Promazine has a wide range of activity arising from its depressant actions on the central nervous system and its alpha-adrenergic blocking and weaker anticholinergic activities. It is a dopamine inhibitor; it inhibits prolactin release-inhibitory factor, considered to be dopamine, thus stimulating the release of prolactin. The turnover of dopamine in the brain is also increased.
Promazine is readily absorbed from the gastro-intestinal tract but is subject to considerable first-pass metabolism in the gut wall. It is also extensively metabolised in the liver and is excreted in the urine and faeces in the form of numerous active and inactive metabolites; there is evidence of enterohepatic recycling. Owing to the first-pass effect, plasma concentrations following oral administration are much lower than those following intramuscular administration.
Moreover, there is very wide intersubject variation in plasma concentrations of Promazine; no simple correlation has been found between plasma concentrations of Promazine and its metabolites, and their therapeutic effect. Paths of metabolism of Promazine include hydroxylation and conjugation with glucuronic acid, N-oxidation, oxidation of a sulphur atom, and dealkylation. Its duration of therapeutic effect can range from a few days to several weeks or possibly longer.
Promazine is very extensively bound to plasma proteins. It is widely distributed in the body and crosses the blood-brain barrier to achieve higher concentrations in the brain than in the plasma. Promazine and its metabolites also cross the placental barrier and are excreted in milk.
None stated.
© All content on this website, including data entry, data processing, decision support tools, "RxReasoner" logo and graphics, is the intellectual property of RxReasoner and is protected by copyright laws. Unauthorized reproduction or distribution of any part of this content without explicit written permission from RxReasoner is strictly prohibited. Any third-party content used on this site is acknowledged and utilized under fair use principles.
