Pharm

Tizanidine

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Tizanidine, Zanaflex

  • See Also
  1. Antispasmodic Skeletal Muscle Relaxant
  2. Baclofen
  • Pathophysiology
  1. Used to reduce severe spasticity (e.g. Spinal Cord Injury, Cerebral Palsy, Multiple Sclerosis)
  • Indications
  • Spasticity
  1. Cerebral Palsy
  2. Multiple Sclerosis
  3. Spinal Cord Injury
  • Contraindications
  1. Not indicated for general musculoskeletal problems
  • Dosing
  1. Start 2 to 4 mg every 8 to 12 hours as needed
  2. May increase to 4 to 8 mg orally every 8 hours as needed
  3. Maximum 24 mg/day (some references list 36 mg/day)
  • Adverse Effects
  1. Sedation (24 to 50% of patients)
  2. Severe Hepatotoxicity
  3. Blood Pressure changes
    1. Hypotension in 7 to 12% of patients
    2. Clonidine effect (risk of Hypotension and rebound Hypertension)
      1. Taper off over 1-2 weeks (risk of Clonidine-like rebound Hypertension effect)
  • Metabolism
  1. CYP1A2 metabolism to inactive metabolites
  2. Half-Life: 2.5 hours
  3. Peak for Tablet: 1 hour Fasting (1.5 hours after eating)
  4. Peak for Capsule: 1 hour Fasting (3 to 4 hours after eating)
  • Resources
  1. Tizanidine Tablet (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=b694225c-1fa9-4726-89a6-fd3f87084248
  • References
  1. (2019) Presc Lett 26(3):15
  2. LoVecchio (2023) Crit Dec Emerg Med 37(6): 32
  3. Wallace (1994) Neurology 44(11): S60-8 [PubMed]