Generic
Tizanidine
4 brands available in the market
At a glance
Tizanidine is a centrally acting muscle relaxant used for muscle spasm, stiffness, and spasticity associated with multiple sclerosis, spinal cord injury, and musculoskeletal conditions.
Description
Tizanidine is a centrally acting skeletal muscle relaxant that acts primarily on the spinal cord. It stimulates presynaptic alpha-2 receptors, inhibiting the release of excitatory amino acids (glutamate, aspartate) that stimulate NMDA receptors. This inhibits polysynaptic signal transmission at the spinal interneuron level and reduces muscle tone.
Indications
- Spasticity due to multiple sclerosis and spinal cord injury
- Painful muscle spasm associated with static and functional disorders of the spine (cervical and lumbar syndromes)
- Following surgery for herniated intervertebral disc or hip osteoarthritis
- Spasticity due to cerebrovascular accidents and cerebral palsy
Therapeutic class
Centrally Acting Skeletal Muscle Relaxants
Pharmacological class
Alpha-2 Adrenergic Agonist
Pharmacology
Tizanidine stimulates presynaptic alpha-2 receptors in the spinal cord, inhibiting the release of excitatory amino acids that stimulate NMDA receptors. This inhibits polysynaptic signal transmission and reduces muscle tone. It also has a moderate central analgesic effect.
Mechanism of action
Reduces muscle spasm and stiffness by stimulating alpha-2 receptors in the spinal cord.
Dosage
Adult Dose (Oral):
- Painful muscle spasm: 2-4 mg three times daily; in severe cases, an extra 2-4 mg at night
- Neurological spasticity: Start 2 mg three times daily; increase by 2-4 mg at half-weekly/weekly intervals; maintenance 12-24 mg/day in 3-4 divided doses; max 36 mg/day
- Elderly (≥65 years): Start at the lowest dose and increase gradually
- Renal impairment (CrCl <25): Start 2 mg once daily
- Hepatic impairment (severe): Contraindicated
Administration
- Can be taken with or without food
- Swallow tablet whole; do not chew, crush, or break
- Take at the same time each day
- Do not stop abruptly (may cause rebound hypertension and tachycardia); taper gradually
Missed dose
If you miss a dose, take it as soon as you remember; if almost time for the next dose, skip it; do not double the dose.
Side effects
Common Side Effects:
- Somnolence, fatigue
- Dizziness
- Dry mouth
- Decreased blood pressure
- Nausea, GI disorder
- Transaminase increase
At Higher Doses:
- Hypotension, bradycardia
- Muscular weakness
- Insomnia, hallucination
- Hepatitis
Precautions & warnings
- Contraindicated in severe hepatic dysfunction
- Contraindicated with CYP1A2 inhibitors (fluvoxamine, ciprofloxacin)
- May cause hypotension, bradycardia; may affect driving ability
- Monitor liver function at baseline and regularly (monthly for first 4 months at doses ≥12 mg)
- Dose adjustment needed in renal impairment
Contraindications
- Hypersensitivity to tizanidine
- Severely impaired hepatic function
- Concomitant use with strong CYP1A2 inhibitors (fluvoxamine, ciprofloxacin)
Drug interactions
- CYP1A2 inhibitors (fluvoxamine, ciprofloxacin, amiodarone, mexiletine, propafenone, cimetidine, fluoroquinolones, rofecoxib, oral contraceptives, ticlopidine): Increased tizanidine plasma levels (33-fold with fluvoxamine; 10-fold with ciprofloxacin); may cause hypotension, somnolence, dizziness, QT prolongation
- Rifampicin: Decreased tizanidine levels by 50%
- Antihypertensives: Hypotension and bradycardia
- Alcohol: Increased sedation and hypotension
- Sedatives, hypnotics, antihistamines: Enhanced sedative effect
Food interactions
Alcohol is unsafe with Tizanidine (excessive sedation and hypotension).
Use in pregnancy
Use in Pregnancy: Limited experience; use only if clearly needed; consult your doctor.
Pregnancy Category: C — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: Probably unsafe; small amounts excreted in rat milk; do not use while breastfeeding; consult your doctor.
Pediatric use
Limited experience in children <18 years; not recommended
Geriatric use
Limited experience in elderly (≥65 years); start at the lowest dose
Renal / hepatic impairment
Renal Impairment: CrCl <25: Start 2 mg once daily; increase gradually; consult your doctor.
Hepatic Impairment: Contraindicated in severe hepatic impairment; caution in moderate; start at the lowest dose; consult your doctor.
Overdose effects
Overdose (up to 400 mg) may cause nausea, vomiting, hypotension, QT prolongation, dizziness, somnolence, miosis, respiratory distress, coma; activated charcoal, forced diuresis; provide symptomatic treatment.
Storage conditions
Store below 30°C in a dry place; keep out of reach and sight of children.
Chemical structure
Tizanidine