Core pharmacology

Class Group

Anti-emetic

Histamine Antagonist

Legacy Cicm Level

Level 3

Introduction

H1-antagonist

Mechanism of action

1. H1 antagonism- VC, vestibular nucleus and CTZ
2. Anti-muscarinic effects- NTS, CTZ, vomit center
3. D2 antagonism (GIT, CTZ)
5-HT3 antagonist

Physiological effects

CVS- IV may cause transient hypotension

CNS- potent sedative and anxiolytic

GIT- decreased LOS tone

Adverse Effects Toxicity

1. Over sedation
2. Paradoxical hyper excitability
3. Anticholinergic
4. Photosensitivity
Jaundice

Absorption

Extensive FPM

Protein binding

93% PB

Volume of distribution

Vd 2.5L/kg

Metabolism

Hepatic conjugation and N-dealkylation

Excretion

2% unchanged in urine.

Half-life

T1/2=7.5-10 hours