Core pharmacology

Class Group

Neuromuscular - Miscellaneous

Legacy Cicm Level

Level 3

Indications Uses

1. MH treatment and prophylaxis
2. Neuroleptic malignant syndrome
3. Ecstasy intoxication
4. Chronic muscle spasms
5. Improve voiding in patients with neuromuscular disorders

Presentation

Orange powder for reconstitution containing mannitol

Mechanism of action

Uncouples the excitation contraction process by binding the ryanodine receptor, thereby preventing the release of calcium from the sarcoplasmic reticulum in striated muscle.
Vascular smooth muscle and cardiac smooth muscle are not primarily dependent on calcium release and are usually not affected.
May produce respiratory failure secondary to skeletal muscle weakness
Produces sedation secondary to GABA-ergic activity

Adverse Effects Toxicity

1. Sedation
2. Hepatotoxicity (chronic use)
3. Pleural effusions (chronic use)
4. Highly irritant if extravasates
5. Diuresis (mannitol)

Absorption

Variable oral absorption

Protein binding

85% protein bound to albumin

Metabolism

Hepatically metabolized

Excretion

Renally excreted

Half-life

T1/2= 3-12 hours

Route And Dose

2.5mg/kg IV every 10-15 mins, up to 10mg/kg
Once resolved, continue giving 1mg/kg every 4-6 hours for 24 hrs.