Tizanidine is an alpha-2 adrenergic agonist used for the short-term treatment of muscle spasticity.

Brand Names
Generic Name
DrugBank Accession Number

Tizanidine is a fast-acting drug used for the management of muscle spasm, which may result from the effects of multiple sclerosis, stroke, an acquired brain injury, or a spinal cord injury 9. It may also be caused by musculoskeletal injury 5. Regardless of the cause, muscle spasticity can be an extremely painful and debilitating condition.

Initially approved by the FDA in 1996, tizanidine is an Alpha-2 adrenergic receptor agonist reducing spasticity by the presynaptic inhibition of excitatory neurotransmitters that cause firing of neurons promoting muscle spasm Label.

Small Molecule
Approved, Investigational
Average: 253.711
Monoisotopic: 253.018893678
Chemical Formula
  • 5-Chloro-4-(2-imidazolin-2-ylamino)-2,1,3-benzothiadiazole
  • Tizanidin
  • Tizanidina
  • Tizanidine
  • Tizanidinum
External IDs
  • AN 021
  • DS 103-282



Tizanidine is indicated for the relief of muscle spasticity, which can interfere with daily activities. The general recommendation is to reserve tizanidine use for periods of time when there is a particular need for relief, as it has a short duration of action Label,11.

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Associated Conditions
Indication TypeIndicationCombined Product DetailsApproval LevelAge GroupPatient CharacteristicsDose Form
Treatment ofAcute low back pain••• •••••
Treatment ofDrug withdrawal headache••• •••••
Treatment ofInsomnia••• •••••
Treatment ofMigraine••• •••••
Management ofMuscle spasticity••••••••••••
Associated Therapies
Contraindications & Blackbox Warnings
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A note on spasticity

Spasticity is an increase in muscle accompanied by uncontrolled, repetitive contractions of skeletal muscles which are involuntary. The patient suffering from muscle spasticity may have reduced mobility and high levels of pain, contributing to poor quality of life and problems performing activities of personal hygiene and care 7.

General effects

Tizanidine is a rapidly acting drug used for the relief of muscle spasticity when it is required for performing specific activities. It acts as an agonist at Alpha-2 adrenergic receptor sites and relieves symptoms of muscle spasticity, allowing the continuation of normal daily activities. In animal models, tizanidine has not been shown to exert direct effects on skeletal muscle fibers or the neuromuscular junction, and has shown no significant effect on monosynaptic spinal reflexes (consisting of the communication between only 1 sensory neuron and 1 motor neuron) 10. The frequency of muscle spasm and clonus are shown to be decreased by tizanidine 9. Tizanidine shows a stronger action on polysynaptic reflexes, which involve several interneurons (relay neurons) communicating with motor neurons stimulating muscle movement 10.

Effects on blood pressure and heart rate

This drug decreases heart rate and blood pressure in humans 4,6. Despite this, rebound hypertension and tachycardia along with increased spasticity can occur when tizanidine is abruptly discontinued 8.

Mechanism of action

Tizanidine reduces spasticity by causing presynaptic inhibition of motor neurons via agonist actions at Alpha-2 adrenergic receptor sites. This drug is centrally acting and leads to a reduction in the release of excitatory amino acids like glutamate and aspartate, which cause neuronal firing that leads to muscle spasm. The above reduction and excitatory neurotransmitter release results in presynaptic inhibition of motor neurons. The strongest effect of tizanidine has been shown to occur on spinal polysynaptic pathways. The anti-nociceptive and anticonvulsant activities of tizanidine may also be attributed to agonist action on Alpha-2 receptors. Tizanidine also binds with weaker affinity to the Alpha-1 receptors, explaining its slight and temporary effect on the cardiovascular system 9.

UAlpha-1 adrenergic receptors
UAlpha-2 adrenergic receptors

This drug undergoes significant first-pass metabolism. After the administration of an oral dose, tizanidine is mostly absorbed. The absolute oral bioavailability of tizanidine is measured to be about 40% Label.

Effect of food on absorption

Food has been shown to increase absorption for both the tablets and capsules. The increase in absorption with the tablet (about 30%) was noticeably higher than the capsule (~10%). When the capsule and tablet were administered with food, the amount absorbed from the capsule was about 80% of the amount absorbed from the tablet Label. It is therefore advisable to take this drug with food for increased absorption, especially in tablet form.

Volume of distribution

Extensively distributed throughout the body. The average steady-state volume of distribution is 2.4 L/kg Label.

Protein binding

About 30% bound to plasma proteins Label.


About 95% of the ingested dose of tizanidine is metabolized. The main enzyme involved in the hepatic metabolism of tizanidine is CYP1A2 Label.

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Route of elimination

This drug is mainly eliminated by the kidney Label.


Approximately 2.5 hours Label.


A note on renal impairment

Tizanidine clearance is found to be decreased by more than 50% in elderly patients with renal insufficiency (creatinine clearance < 25 mL/min) compared to healthy elderly subjects; this would be expected to lead to a longer duration of clinical effect. This drug should be used with caution in patients with renal impairment Label.

Adverse Effects
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LD50 information

Oral LD50 (rat): 414 mg/kg; Subcutaneous LD50 (rat): 282 mg/kg; Oral LD50 (mouse): 235 mg/kg MSDS

Use in pregnancy

Animal studies have determined that this drug causes fetal harm Label. Studies have not been performed in humans, and it is advisable to ensure that tizanidine use in pregnant women should be reserved for cases in which possible benefit clearly outweighs the possible risk to mother and unborn child 11.

Use in breastfeeding

In studies of rat models, this tizanidine was found excreted in the breastmilk with a milk-to-blood ratio of 1.8:1 Label. In young nursing rats, abnormal results were obtained in tests indicative of central nervous system function. Various developmental changes that may have been attributable to the drug were observed. It is unknown whether tizanidine is excreted in human milk. It is a lipid-soluble drug, however, and likely to be excreted into breast milk 11.

Carcinogenesis and mutagenesis

No signs of carcinogenicity were observed in two dietary studies performed in rodent models. Tizanidine was given to mice for 78 weeks at doses reaching a maximum 16 mg/kg (equivalent to twice the maximum recommended human dose). In addition, the drug was given to rats for 104 weeks at doses reaching 9 mg/kg (equivalent to 2.5 times the maximum recommended human dose). There was a lack of a statistically significant increase in the occurrence of tumors in either study group 11.

Tizanidine was not found to be mutagenic or clastogenic in several laboratory essays, including the bacterial Ames test, the mammalian gene mutation test, in addition to the chromosomal aberration test in Chinese hamster cells and several other assays 11.

Not Available
Pharmacogenomic Effects/ADRs
Not Available


Drug Interactions
This information should not be interpreted without the help of a healthcare provider. If you believe you are experiencing an interaction, contact a healthcare provider immediately. The absence of an interaction does not necessarily mean no interactions exist.
1,2-BenzodiazepineThe risk or severity of CNS depression can be increased when Tizanidine is combined with 1,2-Benzodiazepine.
AbaloparatideThe risk or severity of adverse effects can be increased when Tizanidine is combined with Abaloparatide.
AbametapirThe serum concentration of Tizanidine can be increased when it is combined with Abametapir.
AbataceptThe metabolism of Tizanidine can be increased when combined with Abatacept.
AbirateroneThe serum concentration of Tizanidine can be increased when it is combined with Abiraterone.
Food Interactions
  • Avoid alcohol.
  • Take with or without food. Maintain the same schedule with regard to meals, as concentrations increase in the fasted state and decrease in the fed state.


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Product Ingredients
IngredientUNIICASInChI Key
Tizanidine hydrochlorideB53E3NMY5C64461-82-1ZWUKMNZJRDGCTQ-UHFFFAOYSA-N
Product Images
International/Other Brands
Cimbrar (Euroetika) / Musant (Actavis) / Myores (Meprofarm) / Navizan (Caber) / Relaxkov (Blaskov) / Sirdalid (Novartis) / Sirdalud (Novartis) / Sirdalud MR (Novartis) / Sizolan (Dr. Reddy's) / Spaslax (Panion & BF) / Telzanine (Nisshin Seiyaku) / Ternelin (Novartis) / Tizadin (ACL) / Tizaflex (Actavis) / Tizalud (Opsonin) / Tizan (Sun) / Zanpeak (Tatsumi Kagaku) / Zitanid (Novell)
Brand Name Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing EndRegionImage
Tizanidine HydrochlorideCapsule, gelatin coated6 mg/1OralLake Erie Medical DBA Quality Care Products LLC2012-02-06Not applicableUS flag
Tizanidine HydrochlorideCapsule, gelatin coated2 mg/1OralClinical Solutions Wholsesale2012-02-062017-06-21US flag
ZanaflexCapsule6 mg/1OralStat Rx USA2002-08-29Not applicableUS flag
ZanaflexTablet4 mg/1OralPD-Rx Pharmaceuticals, Inc.1997-01-012020-09-30US flag
ZanaflexCapsule6 mg/1OralAcorda Therapeutics, Inc.2005-04-042019-03-31US flag
Generic Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing EndRegionImage
Apo-tizanidineTablet4 mgOralApotex Corporation2004-11-17Not applicableCanada flag
Apo-tizanidineTablet2 mgOralApotex CorporationNot applicableNot applicableCanada flag
Comfort Pac with TizanidineKit; Tablet4 mg/1OralPD-Rx Pharmaceuticals, Inc.2013-07-092018-12-17US flag
Mint-tizanidineTablet4 mgOralMint Pharmaceuticals Inc2023-09-07Not applicableCanada flag
Mylan-tizanidineTablet4 mgOralMylan Pharmaceuticals2006-02-162017-01-09Canada flag
Mixture Products
NameIngredientsDosageRouteLabellerMarketing StartMarketing EndRegionImage
ALGI - B® TABLETASTizanidine hydrochloride (2 mg) + Acetaminophen (325 mg)Tablet, coatedOral2010-05-27Not applicableColombia flag
FLECTADOL CAPSULASTizanidine hydrochloride (2 mg) + Ibuprofen (400 mg)Capsule, coatedOralC.I. FARMACAPSULAS S.A.S. - PLANTA NO. 22006-11-102015-09-03Colombia flag
MIALGILOXTizanidine (2 mg) + Ibuprofen (400 mg)Capsule, coatedOralSEVERIANO FERNÁNDEZ M & CIA. LTDA2017-12-01Not applicableColombia flag
MYOS -NOR F TABLETASTizanidine hydrochloride (2 mg) + Ibuprofen (200 mg)Tablet, coatedOralBLISTECO S.A.S.2008-11-07Not applicableColombia flag
TIZAFEN® TABLETA RECUBIERTATizanidine hydrochloride (2 mg) + Acetaminophen (350 mg)Tablet, coatedOralLABORATORIOSSIEGFRIED S.A.S2006-11-10Not applicableColombia flag


ATC Codes
M03BX02 — Tizanidine
Drug Categories
Chemical TaxonomyProvided by Classyfire
This compound belongs to the class of organic compounds known as benzothiadiazoles. These are heterocyclic aromatic compounds containing a benzene ring fused to a thiadiazole ring. Thiadiazole is a five-membered aromatic heterocycle made up of one sulfur atom and two nitrogen atoms.
Organic compounds
Super Class
Organoheterocyclic compounds
Sub Class
Not Available
Direct Parent
Alternative Parents
Benzenoids / Aryl chlorides / Thiadiazoles / Imidazolines / Heteroaromatic compounds / Guanidines / Propargyl-type 1,3-dipolar organic compounds / Carboximidamides / Azacyclic compounds / Organopnictogen compounds
show 2 more
2,1,3-benzothiadiazole / 2-imidazoline / Aromatic heteropolycyclic compound / Aryl chloride / Aryl halide / Azacycle / Azole / Benzenoid / Carboximidamide / Guanidine
show 10 more
Molecular Framework
Aromatic heteropolycyclic compounds
External Descriptors
imidazoles, benzothiadiazole (CHEBI:63629)
Affected organisms
  • Humans and other mammals

Chemical Identifiers

CAS number
InChI Key


Synthesis Reference

Pavel Hradil, Lubomir Kvapil, Martin Grepl, Jan Novotny, "METHOD FOR THE PREPARATION OF TIZANIDINE HYDROCHLORIDE." U.S. Patent US20110263863, issued October 27, 2011.

General References
  1. Henney HR 3rd, Runyan JD: A clinically relevant review of tizanidine hydrochloride dose relationships to pharmacokinetics, drug safety and effectiveness in healthy subjects and patients. Int J Clin Pract. 2008 Feb;62(2):314-24. doi: 10.1111/j.1742-1241.2007.01660.x. [Article]
  2. Malanga G, Reiter RD, Garay E: Update on tizanidine for muscle spasticity and emerging indications. Expert Opin Pharmacother. 2008 Aug;9(12):2209-15. doi: 10.1517/14656566.9.12.2209 . [Article]
  3. Wagstaff AJ, Bryson HM: Tizanidine. A review of its pharmacology, clinical efficacy and tolerability in the management of spasticity associated with cerebral and spinal disorders. Drugs. 1997 Mar;53(3):435-52. doi: 10.2165/00003495-199753030-00007. [Article]
  4. Mathias CJ, Luckitt J, Desai P, Baker H, el Masri W, Frankel HL: Pharmacodynamics and pharmacokinetics of the oral antispastic agent tizanidine in patients with spinal cord injury. J Rehabil Res Dev. 1989 Fall;26(4):9-16. [Article]
  5. Mense S: Muscle pain: mechanisms and clinical significance. Dtsch Arztebl Int. 2008 Mar;105(12):214-9. doi: 10.3238/artzebl.2008.0214. Epub 2008 Mar 21. [Article]
  6. Taittonen M, Raty H, Kirvela O, Aantaa R, Kanto J: The metabolic effects of oral tizanidine in healthy volunteers. Acta Anaesthesiol Scand. 1995 Jul;39(5):628-32. [Article]
  7. Chang E, Ghosh N, Yanni D, Lee S, Alexandru D, Mozaffar T: A Review of Spasticity Treatments: Pharmacological and Interventional Approaches. Crit Rev Phys Rehabil Med. 2013;25(1-2):11-22. doi: 10.1615/CritRevPhysRehabilMed.2013007945. [Article]
  8. Suarez-Lledo A, Padulles A, Lozano T, Cobo-Sacristan S, Colls M, Jodar R: Management of Tizanidine Withdrawal Syndrome: A Case Report. Clin Med Insights Case Rep. 2018 Feb 13;11:1179547618758022. doi: 10.1177/1179547618758022. eCollection 2018. [Article]
  9. Shirin Ghanavatian; Armen Derian (2019). Tizanidine. StatPearls.
  10. Reflexes: Components of a Reflex Arc [Link]
  11. Canadian monograph, Tizanidine [File]
Human Metabolome Database
KEGG Compound
PubChem Compound
PubChem Substance
Therapeutic Targets Database
RxList Drug Page
Drugs.com Drug Page
FDA label
Download (329 KB)
Download (24.2 KB)

Clinical Trials

Clinical Trials
4CompletedTreatmentBack Pain Lower Back1
4CompletedTreatmentUnilateral Inguinal Hernia1
4CompletedTreatmentUpper Limb Spasticity1
4Not Yet RecruitingTreatmentMajor Depressive Disorder (MDD)1


  • Acorda therapeutics inc
  • Actavis elizabeth llc
  • Actavis totowa llc
  • Alphapharm party ltd
  • Apotex inc
  • Barr laboratories inc
  • Caraco pharmaceutical laboratories ltd
  • Corepharma llc
  • Dr reddys laboratories inc
  • Ivax pharmaceuticals inc sub teva pharmaceuticals usa
  • Mylan pharmaceuticals inc
  • Sandoz inc
  • Teva pharmaceuticals usa inc
  • Acorda Therapeutics
  • Aidarex Pharmacuticals LLC
  • Alphapharm Party Ltd.
  • Altura Pharmaceuticals Inc.
  • Amerisource Health Services Corp.
  • Amneal Pharmaceuticals
  • Apotex Inc.
  • A-S Medication Solutions LLC
  • Bryant Ranch Prepack
  • Caraco Pharmaceutical Labs
  • Cardinal Health
  • Corepharma LLC
  • Deca Pharmaceuticals LLC
  • Dispensing Solutions
  • Diversified Healthcare Services Inc.
  • Doctor Reddys Laboratories Ltd.
  • Elan Pharmaceuticals Inc.
  • Eon Labs
  • Genpharm LP
  • H.J. Harkins Co. Inc.
  • Heartland Repack Services LLC
  • Innoviant Pharmacy Inc.
  • Ivax Pharmaceuticals
  • Keltman Pharmaceuticals Inc.
  • Lake Erie Medical and Surgical Supply
  • Major Pharmaceuticals
  • Murfreesboro Pharmaceutical Nursing Supply
  • Mylan
  • Nucare Pharmaceuticals Inc.
  • Palmetto Pharmaceuticals Inc.
  • Par Pharmaceuticals
  • Patheon Inc.
  • PD-Rx Pharmaceuticals Inc.
  • Physicians Total Care Inc.
  • Preferred Pharmaceuticals Inc.
  • Prepak Systems Inc.
  • Rebel Distributors Corp.
  • Redpharm Drug
  • Resource Optimization and Innovation LLC
  • Southwood Pharmaceuticals
  • St Mary's Medical Park Pharmacy
  • Stat Rx Usa
  • Torpharm Inc.
  • UDL Laboratories
  • Vangard Labs Inc.
Dosage Forms
Tablet, coatedOral
Capsule, extended releaseOral6 mg
Kit; tabletOral4 mg/1
CapsuleOral15.000 mg
Solution / drops
TabletOral400000 mg
Capsule, coatedOral
TabletOral0.002 g
Tablet, film coatedOral4 mg
Tablet, film coatedOral400000 mg
Solution / drops; tabletOphthalmic
Capsule, delayed release6 mg
TabletOral2.288 mg
TabletOral6 MG
CapsuleOral6 mg
TabletOral200000 mg
TabletOral2 mg/1
CapsuleOral2 mg/1
Capsule, gelatin coatedOral2 mg/1
Capsule, gelatin coatedOral6 mg/1
TabletOral4 mg/1
Tablet, film coatedOral
CapsuleOral4 mg/1
CapsuleOral6 mg/1
Capsule, gelatin coatedOral4 mg/1
TabletOral2 mg
TabletOral4 mg
Unit descriptionCostUnit
Zanaflex 6 mg capsule4.79USD capsule
Zanaflex 4 mg capsule3.2USD capsule
Zanaflex 2 mg capsule2.52USD capsule
Zanaflex 4 mg tablet2.29USD tablet
Tizanidine hcl 4 mg tablet1.49USD tablet
Zanaflex 2 mg tablet1.42USD tablet
Tizanidine hcl 2 mg tablet1.25USD tablet
DrugBank does not sell nor buy drugs. Pricing information is supplied for informational purposes only.
Patent NumberPediatric ExtensionApprovedExpires (estimated)Region
US6455557No2002-09-242021-11-28US flag


Experimental Properties
melting point (°C)280https://www.lookchem.com/Tizanidine-hydrochloride/
boiling point (°C)391.2https://www.lookchem.com/Tizanidine/
water solubilityslightly solubleFDA label
Predicted Properties
Water Solubility0.133 mg/mLALOGPS
pKa (Strongest Basic)7.49Chemaxon
Physiological Charge1Chemaxon
Hydrogen Acceptor Count5Chemaxon
Hydrogen Donor Count2Chemaxon
Polar Surface Area62.2 Å2Chemaxon
Rotatable Bond Count1Chemaxon
Refractivity64.77 m3·mol-1Chemaxon
Polarizability23.97 Å3Chemaxon
Number of Rings3Chemaxon
Rule of FiveYesChemaxon
Ghose FilterYesChemaxon
Veber's RuleNoChemaxon
MDDR-like RuleNoChemaxon
Predicted ADMET Features
Human Intestinal Absorption+1.0
Blood Brain Barrier+0.8592
Caco-2 permeable+0.5323
P-glycoprotein substrateSubstrate0.6545
P-glycoprotein inhibitor INon-inhibitor0.8365
P-glycoprotein inhibitor IINon-inhibitor0.7953
Renal organic cation transporterInhibitor0.6577
CYP450 2C9 substrateNon-substrate0.7953
CYP450 2D6 substrateNon-substrate0.8018
CYP450 3A4 substrateNon-substrate0.5795
CYP450 1A2 substrateNon-inhibitor0.5248
CYP450 2C9 inhibitorNon-inhibitor0.7117
CYP450 2D6 inhibitorNon-inhibitor0.7867
CYP450 2C19 inhibitorNon-inhibitor0.6353
CYP450 3A4 inhibitorNon-inhibitor0.781
CYP450 inhibitory promiscuityHigh CYP Inhibitory Promiscuity0.5
Ames testNon AMES toxic0.6538
BiodegradationNot ready biodegradable1.0
Rat acute toxicity2.6573 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.6935
hERG inhibition (predictor II)Non-inhibitor0.8907
ADMET data is predicted using admetSAR, a free tool for evaluating chemical ADMET properties. (23092397)


Mass Spec (NIST)
Not Available
SpectrumSpectrum TypeSplash Key
Predicted GC-MS Spectrum - GC-MSPredicted GC-MSsplash10-0a4i-3960000000-3aca4c577af73cfa3997
Mass Spectrum (Electron Ionization)MSsplash10-0udi-5490000000-5ee0610f321160b63c82
Predicted MS/MS Spectrum - 10V, Positive (Annotated)Predicted LC-MS/MSsplash10-0udi-0090000000-425432ba738571ef78a8
Predicted MS/MS Spectrum - 10V, Negative (Annotated)Predicted LC-MS/MSsplash10-0udi-1090000000-6095a8134c8c22b9ea88
Predicted MS/MS Spectrum - 20V, Positive (Annotated)Predicted LC-MS/MSsplash10-0udi-0090000000-1771655e532ce4034040
Predicted MS/MS Spectrum - 20V, Negative (Annotated)Predicted LC-MS/MSsplash10-001i-9500000000-6aa2874f4d8f69b1cc00
Predicted MS/MS Spectrum - 40V, Positive (Annotated)Predicted LC-MS/MSsplash10-000i-2950000000-98a6513db9d8a7e73d3c
Predicted MS/MS Spectrum - 40V, Negative (Annotated)Predicted LC-MS/MSsplash10-001i-9100000000-fde5057917848f058e94
Predicted 1H NMR Spectrum1D NMRNot Applicable
Predicted 13C NMR Spectrum1D NMRNot Applicable
Chromatographic Properties
Collision Cross Sections (CCS)
AdductCCS Value (Å2)Source typeSource
DarkChem Lite v0.1.0
DarkChem Lite v0.1.0
DeepCCS 1.0 (2019)
DarkChem Lite v0.1.0
DarkChem Lite v0.1.0
DeepCCS 1.0 (2019)
DarkChem Lite v0.1.0
DarkChem Lite v0.1.0
DeepCCS 1.0 (2019)


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1. Nischarin
Pharmacological action
General Function
Phosphatidylinositol binding
Specific Function
Acts either as the functional imidazoline-1 receptor (I1R) candidate or as a membrane-associated mediator of the I1R signaling. Binds numerous imidazoline ligands that induces initiation of cell-si...
Gene Name
Uniprot ID
Uniprot Name
Molecular Weight
166627.105 Da
  1. Tanabe M, Hashimoto M, Ono H: Imidazoline I(1) receptor-mediated reduction of muscle rigidity in the reserpine-treated murine model of Parkinson's disease. Eur J Pharmacol. 2008 Jul 28;589(1-3):102-5. doi: 10.1016/j.ejphar.2008.06.013. Epub 2008 Jun 7. [Article]
  2. Talakoub R, Abbasi S, Maghami E, Zavareh SM: The effect of oral tizanidine on postoperative pain relief after elective laparoscopic cholecystectomy. Adv Biomed Res. 2016 Feb 8;5:19. doi: 10.4103/2277-9175.175905. eCollection 2016. [Article]
  3. Canadian monograph, Tizanidine [File]
  4. FDA label, Zanaflex [File]
Protein group
Pharmacological action
General Function
Protein heterodimerization activity
Specific Function
This alpha-adrenergic receptor mediates its action by association with G proteins that activate a phosphatidylinositol-calcium second messenger system. Its effect is mediated by G(q) and G(11) prot...

  1. Takayanagi I, Konno F, Ishii C, Takemasa T, Yanagida Y, Shimizu M, Mori H, Sugane H: Actions of tizanidine on alpha 1-and alpha 2-adrenoceptors in the peripheral tissues. Gen Pharmacol. 1984;15(3):239-41. [Article]
  2. Takayanagi I, Harada M, Koike K, Satoh M: Differences in alpha 1-adrenoceptor mechanisms for phenylephrine and tizanidine in rabbit thoracic aorta and common iliac artery. Can J Physiol Pharmacol. 1991 Dec;69(12):1819-24. [Article]
  3. Shirin Ghanavatian; Armen Derian (2019). Tizanidine. StatPearls.
Protein group
Pharmacological action
General Function
Thioesterase binding
Specific Function
Alpha-2 adrenergic receptors mediate the catecholamine-induced inhibition of adenylate cyclase through the action of G proteins. The rank order of potency for agonists of this receptor is oxymetazo...

  1. Piletz JE, Zhu H, Chikkala DN: Comparison of ligand binding affinities at human I1-imidazoline binding sites and the high affinity state of alpha-2 adrenoceptor subtypes. J Pharmacol Exp Ther. 1996 Nov;279(2):694-702. [Article]
  2. Giovannitti JA Jr, Thoms SM, Crawford JJ: Alpha-2 adrenergic receptor agonists: a review of current clinical applications. Anesth Prog. 2015 Spring;62(1):31-9. doi: 10.2344/0003-3006-62.1.31. [Article]
  3. Leiphart JW, Dills CV, Levy RM: Alpha2-adrenergic receptor subtype specificity of intrathecally administered tizanidine used for analgesia for neuropathic pain. J Neurosurg. 2004 Oct;101(4):641-7. doi: 10.3171/jns.2004.101.4.0641. [Article]
  4. Fairbanks CA, Stone LS, Wilcox GL: Pharmacological profiles of alpha 2 adrenergic receptor agonists identified using genetically altered mice and isobolographic analysis. Pharmacol Ther. 2009 Aug;123(2):224-38. doi: 10.1016/j.pharmthera.2009.04.001. Epub 2009 Apr 23. [Article]
  5. Zanaflex FDA label [File]


Pharmacological action
General Function
Oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen
Specific Function
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally un...
Gene Name
Uniprot ID
Uniprot Name
Cytochrome P450 1A2
Molecular Weight
58293.76 Da
  1. Wang B, Zhou SF: Synthetic and natural compounds that interact with human cytochrome P450 1A2 and implications in drug development. Curr Med Chem. 2009;16(31):4066-218. [Article]
  2. Shellenberger MK, Groves L, Shah J, Novack GD: A controlled pharmacokinetic evaluation of tizanidine and baclofen at steady state. Drug Metab Dispos. 1999 Feb;27(2):201-4. [Article]
  3. Karjalainen MJ, Neuvonen PJ, Backman JT: Rofecoxib is a potent, metabolism-dependent inhibitor of CYP1A2: implications for in vitro prediction of drug interactions. Drug Metab Dispos. 2006 Dec;34(12):2091-6. doi: 10.1124/dmd.106.011965. Epub 2006 Sep 19. [Article]
  4. Flockhart Table of Drug Interactions [Link]
  5. Tizanidine FDA label [File]

Drug created at June 13, 2005 13:24 / Updated at May 27, 2024 02:37