Overview
Tizanidine is a centrally acting alpha-2 adrenergic agonist used to treat spasticity in adults. It reduces muscle tone by inhibiting spinal motor neurons, but carries risks of hypotension, sedation, and liver injury that require careful monitoring.
Mechanism of Action
Tizanidine is a centrally acting alpha-2 adrenergic agonist that reduces spasticity by increasing presynaptic inhibition of motor neurons in the spinal cord, decreasing the release of excitatory neurotransmitters.
Indications
- Treatment of spasticity in adults
Common Doses
- 2 mg
- 4 mg
- 6 mg
Dosage
Individualized dosing starting low and titrating gradually based on response and tolerability. Typically administered in divided doses 2-4 times daily.
Contraindications
- Concurrent use of strong CYP1A2 inhibitors
- History of hypersensitivity to tizanidine or its ingredients
Side Effects
- Hypotension
- Liver injury
- Sedation
- Hallucinations/psychotic-like symptoms
- Hypersensitivity reactions including anaphylaxis and angioedema
- Withdrawal reactions upon abrupt discontinuation
Interactions
- Strong CYP1A2 inhibitors increase tizanidine exposure and toxicity risk
- Additive CNS depression with alcohol and other CNS depressants
Counseling Points
- Take exactly as prescribed; do not increase dose without medical supervision
- Avoid alcohol and other CNS depressants
- Be aware of potential sedation and avoid driving or operating machinery until effects are known
- Monitor for signs of hypotension, liver problems, or unusual mental changes
- Do not stop abruptly; taper under medical supervision
- Report any signs of allergic reaction immediately