Tizanidine

Tizanidine is a short-acting drug for the management of spasticity. Because of the short duration of effect, treatment with tizanidine should be reserved for those daily activities and times when relief of spasticity is most important.

• Tizanidine is available under the following different brand names: Zanaflex.

Dosages of Tizanidine:

Adult Dosage Forms and Strengths

Tablet

• 2 mg
• 4 mg

Capsule

• 2 mg
• 4 mg
• 6 mg

Dosing Considerations – Should be Given as Follows:

Muscle Spasticity

• Spasticity associated with multiple sclerosis and spinal cord injury
• Initial: 2 mg orally every 6-8 hours as needed; no more than 3 doses every 24 hours
• Maintenance: Titrate in 2-4 mg/day increments to optimum effect with minimum 1-4 days between dose increments
• Not to exceed 36 mg/day; single doses greater than 16 mg not studied
• To discontinue taper gradually; decrease by 2-4 mg daily

Dosing Modifications

Renal impairment

• CrCl less than 25 mL/min: Use caution; clearance reduced greater than 50%
• CrCl greater tha25 mL/min: Not studied; use caution

Hepatic impairment

• Close monitoring of adverse drug reactions (ADRs) (e.g., hypotension); avoid in severe impairment

Dosing Considerations

• Pediatric: Not recommended

Common Side effects of Tizanidine include:

• Dry mouth
• Drowsiness
• Dizziness
• Weakness or lack of energy
• Blurred vision
• Constipation
• Infection
• Liver function test abnormalities
• Speech disorder (3%)
• Vomiting
• Urinary frequency
• Urinary tract infection (UTI)

Other side effects of tizanidine include:

• Slow heart rate
• Low blood pressure (hypotension)
• Dizziness upon standing
• Fainting (rare)

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Severe Interactions of tizanidine include:
  • None
• Mild Interactions of tizanidine include:
  • candesartan
  • citalopram
  • clobazam
  • deferasirox
  • eprosartan
  • ethinylestradiol
  • irbesartan
  • losartan
  • lurasidone
  • maraviroc
  • nitroglycerin rectal
  • obeticholic acid
  • olmesartan
  • sacubitril/valsartan
  • telmisartan
  • teriflunomide
  • valsartan
  • vemurafenib
• Tizanidine has mild interactions with at least 84 different drugs.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns, or for more information about this medicine.

Warnings

• This medication contains tizanidine
• Do not take Zanaflex if you are allergic to tizanidine or any ingredients contained in this drug
• Keep out of reach of children
• In case of overdose, get medical help or contact a Poison Control Center immediately

Contraindications

• Hypersensitivity
• Concomitant ciprofloxacin or fluvoxamine, or other potent CYP1A2 inhibitors

Effects of Drug Abuse

• No information available

Short-Term Effects

• See "What Are Side Effects Associated with Using Tizanidine?"

Long-Term Effects

• See "What Are Side Effects Associated with Using Tizanidine?"

Cautions

• Potential for hypotension
• Caution in renal/hepatic impairment
• Women on oral contraceptives
• Hepatotoxicity may occur; monitor aminotransferases before and during use
• Sedation may occur (dose-related); may potentiate the effect of sedative drugs or ethanol
• Visual hallucinations may occur
• CYP1A2 inducers may decrease levels
• Rebound hypertension, tachycardia, and hypertonia reported upon abrupt discontinuation; decrease doses slowly in patients taking concomitant narcotics or high doses (20-28 mg/day) for prolonged periods

Pregnancy and Lactation

• Use tizanidine with caution during pregnancy if benefits outweigh risks
• Animal studies show risk and human studies are not available, or neither animal nor human studies were done
• Tizanidine may be excreted in breast milk due to its lipophilic nature; use caution if breastfeeding