Tizanidine

Tizanidine
Clinical data
Pronunciation/taɪˈzænɪdiːn/ tye-ZAN-i-deen
Trade namesZanaflex, Sirdalud, and others
Other names4-Chloro-N-(4,5-dihydro-1H-imidazol-2-yl)-8-thia-7,9-diazabicyclo[4.3.0]nona-2,4,6,9-tetraen-5-amine
AHFS/Drugs.comMonograph
MedlinePlusa601121
License data
Routes of
administration		By mouth
Drug classα2-adrenergic receptor agonist
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability~40%[1]
Protein binding~30%
MetabolismLiver (CYP1A2, 95%)
Elimination half-life2.54 hours (tizanidine), 20–40 hours (inactive metabolites)[1]
ExcretionUrine (60%), feces (20%)
Identifiers
  • 5-Chloro-N-(4,5-dihydro-1H-imidazol-2-yl)benzo[c] [1,2,5]thiadiazol-4-amine
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
KEGG
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.125.400 Edit this at Wikidata
Chemical and physical data
FormulaC9H8ClN5S
Molar mass253.71 g·mol−1
3D model (JSmol)
  • Clc1ccc3nsnc3c1NC/2=N/CCN\2
  • InChI=1S/C9H8ClN5S/c10-5-1-2-6-8(15-16-14-6)7(5)13-9-11-3-4-12-9/h1-2H,3-4H2,(H2,11,12,13) checkY
  • Key:XFYDIVBRZNQMJC-UHFFFAOYSA-N checkY
  (verify)

Tizanidine, sold under the brand name Zanaflex among others, is an alpha-2 (α2) adrenergic receptor agonist,[2] similar to clonidine, that is used to treat muscle spasticity due to spinal cord injury, multiple sclerosis, and spastic cerebral palsy.[3] Effectiveness appears similar to baclofen or diazepam.[4] It is taken by mouth.[5]

Common side effects of tizanidine include dry mouth, sleepiness, weakness, and dizziness.[5] Serious side effects may include low blood pressure, liver problems, psychosis, and QT prolongation.[5] It is unclear if use in pregnancy and breastfeeding is safe.[6] It is an α2-adrenergic agonist, but how it works is not entirely clear.[5]

Tizanidine was approved for medical use in the United States in 1996.[5] It is available as a generic medication.[3] In 2022, it was the 94th most commonly prescribed medication in the United States, with more than 6 million prescriptions.[7][8]

  1. ^ a b Cite error: The named reference Zanaflex PI was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Katzung was invoked but never defined (see the help page).
  3. ^ a b British national formulary: BNF 76 (76 ed.). Pharmaceutical Press. 2018. p. 1094. ISBN 9780857113382.
  4. ^ Kamen L, Henney HR, Runyan JD (February 2008). "A practical overview of tizanidine use for spasticity secondary to multiple sclerosis, stroke, and spinal cord injury". Current Medical Research and Opinion. 24 (2): 425–439. doi:10.1185/030079908X261113. PMID 18167175. S2CID 73086671.
  5. ^ a b c d e "Tizanidine Hydrochloride Monograph for Professionals". Drugs.com. American Society of Health-System Pharmacists. Retrieved 3 March 2019.
  6. ^ "Tizanidine Pregnancy and Breastfeeding Warnings". Drugs.com. Retrieved 3 March 2019.
  7. ^ "The Top 300 of 2022". ClinCalc. Archived from the original on 30 August 2024. Retrieved 30 August 2024.
  8. ^ "Tizanidine Drug Usage Statistics, United States, 2013 - 2022". ClinCalc. Retrieved 30 August 2024.