Core pharmacology

Class Group

(CCB) Ca channel blocker – Class II

Legacy Cicm Level

Level 2

Introduction

Dihydropyridine calcium channel blocker

Indications Uses

Treatment and prevention of cerebral vasospasm after SAH
Also used in migraine, CVA and drug resistant epilepsy can pass the blood-brain barrier

Presentation

IV 200mcg/ml with ethanol and macrogol
PO 30mg tablets

Mechanism of action

Binds to N binding site of L-type Ca channel on vascular smooth muscle to reduce intracellular Ca.

Physiological effects

CVS: systolic and diastolic hypotension,
1mcg/kg/h → ↑CO+30%
CNS: increases CBF+18% without steal, blunts cardiovascular responses to surgical
stimulus/intubation

Adverse Effects Toxicity

Decreases SVR and can increase CO (overall, May drop BP)

Absorption

PO/IV.
BA 30% Well absorbed high first pass metabolism

Distribution

Highly lipid sol – use cerebral vasospasm

Protein binding

98%

Volume of distribution

1-2 L/kg

Metabolism

Demethylation and dehydrogenation to inactive pyridine analogue.

Excretion

Inactive metabolites urine and faeces.

Half-life

2-4 hrs

Route And Dose

60mg Q4h PO or 20mcg/kg/hr IV