Muscle Relaxant — Alpha-2 Agonist

Tizanidine

Brand names: Zanaflex

Tizanidine is a centrally acting muscle relaxant used to relieve spasticity associated with multiple sclerosis or spinal cord injury and disease.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It is an alpha-2 adrenergic agonist that reduces excitatory interneurone activity in the spinal cord, decreasing the release of excitatory amino acids and thereby lowering muscle tone.

Prescribing in practice

It is contraindicated with potent CYP1A2 inhibitors such as fluvoxamine and ciprofloxacin, which can dramatically raise its levels and cause profound hypotension and sedation.
Hypotension, drowsiness and dry mouth are common, and it should be withdrawn gradually to avoid rebound hypertension and tachycardia.
Hepatotoxicity can occur, so liver function should be checked where clinically indicated.

Monitoring

Monitor blood pressure, sedation and liver function, particularly during dose titration.

Counselling the patient

Rise slowly from sitting or lying, as the medicine can lower blood pressure and cause dizziness.
Do not stop it suddenly and avoid alcohol, which adds to drowsiness.

Evidence & guidelines

Its efficacy in reducing spasticity is supported by randomised controlled trials in multiple sclerosis and spinal cord disorders.

Reference: NICE NG109 (Spasticity); MHRA Tizanidine Drug Interaction Warning; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways