Dantrolene sodium

How it works

It acts directly on skeletal muscle by inhibiting calcium release from the sarcoplasmic reticulum through the ryanodine receptor, reducing excitation-contraction coupling and muscle rigidity.

Prescribing in practice

• In a malignant hyperthermia crisis it must be reconstituted and given without delay alongside stopping the triggering agent and active cooling, so adequate stock must be immediately accessible wherever volatile anaesthetics or suxamethonium are used.
• Oral use for spasticity carries a risk of dose-related hepatotoxicity, including fatal hepatitis, so liver function must be assessed.
• It can cause marked muscle weakness, drowsiness and dizziness, which may impair swallowing and mobility.

Monitoring

In acute use monitor temperature, acid-base status, electrolytes, potassium and cardiovascular and renal function; with chronic oral use monitor liver function.

Counselling the patient

• Advise patients on long-term oral therapy to report jaundice, dark urine, nausea or unusual fatigue.
• Warn that muscle weakness and drowsiness may affect driving and daily activities.

Evidence & guidelines

Its central role in malignant hyperthermia is reflected in established anaesthetic emergency guidance, which stresses immediate availability and prompt administration.