Skeletal muscle relaxants

Question 1

Succinylcholine

What are the uses, mechanims and side effects?

Answer 1

Uses: Muscle relaxant during surgery or other procedures

Mechanism: binds nicotinic Ach receptor (non-selective cation channel) and depolarizes NM end plate. Not degraded by acetylcholinesterase

Side effects: Malignant hyperthermia, severe hyperkalemia resulting in cardiac arrhythmias in patients with burns, mypoathies, serious trauma and denervation, bradycardia from parasympathetic or tachycardia from sympathetic

Question 2

Atracurium

Answer 2

Nondepolarizing NM-blocking agent. Releases histamine which can cause decrease in BP, flushing and bronchoconstriction. Metabolized to laudanosine which can cause seizures

Question 3

Baclofen

Answer 3

Muscle relaxant that affects GABA-B receptors in spinal cord

Question 4

Dantrolene

Answer 4

Use: Muscle relaxant effective in malignant hyperthermia

Mechanism: acts on ryanodine recetors on the SR to prevent release of calcium into cytosol

Side effects: