Core pharmacology

Class Group

Opiate Analgesic

Legacy Cicm Level

Level 2

Introduction

synthetic phenylpiperdine derivative of fentanyl with a unique metabolism

Indications Uses

1. to provide the analgesic component in general anaesthesia
2. to provide analgesia/sedation in intensive care
3. to provide analgesia during labour when regional anaesthesia is not in
use
4. to provide analgesia/sedation during ‘awake’ fibreoptic intubation.

Presentation

white crystalline powder for reconstitution

Main Action

Pure mu receptor agonist

Mechanism of action

Binds primarily to inhibitory G-Protein Coupled μ-opioid receptors→ ↑adenylyl cyclase→ ↓cAMP→ hyperpolarization of cell→↓neurotransmitter release

Physiological effects

inhibitory action,
modulating the pain response to produce analgesia.

shares many of its actions with morphine and
related compounds

Adverse Effects Toxicity

Bradycardia, hypotension, muscle rigidity,
May contribute to hyperalgesia
following prolonged infusion

Absorption

IV only

onset / duration 1-3 minutes

Distribution

relative lipid sol 50

rapid redistribution
pKa 7.1 (70% union)

Protein binding

Prot bind ~70% (1 acid glycoprotein)

Volume of distribution

Vd 0.3L/kg kids

Metabolism

Rapid metabolism via blood and Plasma esterase
- used in liver/ renal disease, different age, sex, body habitus without sign dose modificn

Excretion

excretion urine

Half-life

half life Terminal: 10-20 minutes; effective: 3-10 minutes
No CSHT

Special Points

Clearance of metabolite remifentanil acid - prolonged in renal impairment (up to 268 hrs)

Metabolite concentration significantly increased in ICU patients with mod-severe renal impairment – but no evidence of clinically significant mu-opioid effects

Remifentanil not extracted during RRT.
Metabolite extracted 25-35% during hemodialysis.

Route And Dose

Dose 1mcg/kg bolus, titrate eff¬ect

(relative potency 50-100)