Class: Centrally Acting Skeletal Muscle Relaxant, Alpha-2 Agonist
Dosage Forms. Capsule: 2 mg, 4 mg, 6 mg; Tablet: 2 mg, 4 mg
Common FDA Label Indication, Dosing, and Titration.
1. Spasticity: 4 mg po daily, may titrate to 8 mg po q6-8h with max dose of 36 mg/d
1. Acute pain: 12 mg/d po alone or in combination with NSAIDs
MOA. Tizanidine is a centrally acting muscle relaxant. The drug is an imidazole derivative, structurally unrelated to other muscle relaxants. The drug is antispastic and has shown efficacy in animal models of hypertonia. The mechanism of action of the drug remains unknown. Tizanidine is an agonist of α2-adrenergic receptors; however, it does not have antihypertensive properties.
Drug Characteristics: Tizanidine
Medication Safety Issues: Tizanidine
Drug Interactions: Tizanidine
Adverse Reactions: Tizanidine
Efficacy Monitoring Parameters. Reduction in pain and muscle spasms, reduction in passive limb movement.
Toxicity Monitoring Parameters. Monitor BP, LFTs, SCr, CBC.
Key Patient Counseling Points. Be cautious of risk of dizziness and somnolence when initiating therapy; do not drive until effects of drug are known. Rise slowly from a lying/sitting position, as this drug may cause hypotension. May cause xerostomia (dry mouth) and asthenia (weakness).
Clinical Pearls. While this drug may be taken with or without food, patients should take the drug in the same way (fasting or fed) every time to avoid inconsistent absorption patterns and resulting changes in efficacy and adverse effects. Effect of food on extent of absorption differs for tablets and capsules.