Tizanidine

Brand names: Zanaflex®

Chemical formula:

Drug Forms:
• Tizanidine Hydrochloride Oral capsule (below)
• Tizanidine Hydrochloride Oral tablet
• Tizanidine tablets or capsules

Español:
• Tizanidina Clorhidrato, Cápsula oral
• Tizanidina Clorhidrato, Tableta oral
• Tabletas o cápsulas de tizanidina

Tizanidine Hydrochloride Oral capsule

What is this medicine?

TIZANIDINE helps to relieve muscle spasms. It may be used to help in the treatment of multiple sclerosis and spinal cord injury.

This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
•kidney disease
•liver disease
•low blood pressure
•mental disorder
•an unusual or allergic reaction to tizanidine, other medicines, lactose (tablets only), foods, dyes, or preservatives
•pregnant or trying to get pregnant
•breast-feeding

How should I use this medicine?

Take this medicine by mouth with a full glass of water. Take this medicine on an empty stomach, at least 30 minutes before or 2 hours after food. Do not take with food unless you talk with your doctor. Follow the directions on the prescription label. Take your medicine at regular intervals. Do not take your medicine more often than directed. Do not stop taking except on your doctor's advice. Suddenly stopping the medicine can be very dangerous.

Talk to your pediatrician regarding the use of this medicine in children.

Patients over 65 years old may have a stronger reaction and need a smaller dose.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.
NOTE: This medicine is only for you. Do not share this medicine with others.

What may interact with this medicine?

Do not take this medicine with any of the following medications:
•ciprofloxacin
•clonidine
•fluvoxamine
•guanabenz
•guanfacine
•methyldopa

This medicine may also interact with the following medications:
•acyclovir
•alcohol
•antihistamines
•baclofen
•barbiturates like phenobarbital
•benzodiazepines
•cimetidine
•famotidine
•female hormones, like estrogens or progestins and birth control pills
•medicines for high blood pressure
•medicines for irregular heartbeat
•medicines for pain like codeine, morphine, and hydrocodone
•medicines for sleep
•rofecoxib
•some antibiotics like levofloxacin, ofloxacin
•ticlopidine
•zileuton

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

What should I watch for while using this medicine?

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.

Your mouth may get dry. Chewing sugarless gum or sucking hard candy, and drinking plenty of water may help. Contact your doctor if the problem does not go away or is severe.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:
•allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
•blurred vision
•fainting spells
•hallucinations
•nausea or vomiting
•nervousness
•redness, blistering, peeling or loosening of the skin, including inside the mouth
•slow or irregular heartbeat, palpitations, or chest pain
•yellowing of the skin or eyes

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):
•dizziness
•drowsiness
•dry mouth
•tiredness or weakness

This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Where should I keep my medicine?

Keep out of the reach of children.

Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Throw away any unused medicine after the expiration date.

Last updated: 7/1/2002

Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.

Tizanidine
Systematic (IUPAC) name
5-chloro-N-(4,5-dihydro-1H-imidazol-2-yl)-2,1,3-benzothiadiazol-4-amine
Identifiers
CAS number	51322-75-9
ATC code	M03BX02
PubChem	5487
DrugBank	APRD00128
ChemSpider	5287
Chemical data
Formula	C9H8ClN5S
Mol. mass	253.712
SMILES	eMolecules & PubChem
Synonyms	4-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
Pharmacokinetic data
Bioavailability	?
Protein binding	30%
Metabolism	CYP 1A2
Half life	2.54 hours
Excretion	?
Therapeutic considerations
Pregnancy cat.	?
Legal status	Rx-Only, Unscheduled
Routes	Oral, Intranasal, Injection
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Tizanidine (brandnames Zanaflex, Sirdalud) is a drug that is used as a muscle relaxant. It is a centrally acting α-2 adrenergic agonist. It is used to treat the spasms, cramping, and tightness of muscles caused by medical problems such as multiple sclerosis, spastic diplegia, back pain, or certain other injuries to the spine or central nervous system. It is also prescribed off-label for migraine headaches, as a sleep aid, and as an anticonvulsant. It is also prescribed for some symptoms of fibromyalgia^[1].

Tizanidine may cause hypotension, so caution is advised when it is used in patients who have a history of orthostatic hypotension. Use caution with this drug as it can be very strong even at the 2 mg dose. Also use caution when switching from gel cap to tablet form and vice versa.

Contents 1 Availability 2 Side effects 3 Interactions 4 References

Availability

Tizanidine is available in tablets with "cor 138" on one side and 2 scores on the back that create an X, or R179 on one side and a single score through the middle of the back, or a white oval pill with R180 on one side and 2 scores on the back that create an X, or a round white tablet with E 44 on one side, and is double scored on the other side. It is also found as a circular white pill with the number 503 on one side and X-scored on the back^[2].

Tizanidine is supplied as 2 and 4 mg tablets for oral administration, and in gel cap form in doses of 2 mg, 4 mg, and 6 mg.

The tablets are composed of the active ingredient, tizanidine hydrochloride (2.288 mg equivalent to 2 mg tizanidine base and 4.576 mg equivalent to 4 mg tizanidine base), and the inactive ingredients, silicon dioxide colloidal, stearic acid, microcrystalline cellulose and anhydrous lactose.

Side effects

Tizanidine use occasionally causes drug induced liver injury. In controlled clinical studies, approximately 5% of patients treated with Zanaflex had elevations of liver function tests (ALT, AST) to greater than 3 times the upper limit of normal (or 2 times if baseline levels were elevated).^{[citation needed]}

Tizanidine use has been associated with hallucinations. Visual hallucinations and delusions have been reported in 5 of 170 patients (3%) in two North American controlled clinical studies.^{[citation needed]}

If therapy needs to be discontinued, especially in patients who have been receiving high doses for long periods, the dose should be decreased slowly to minimize the risk of withdrawal and rebound hypertension, tachycardia, and hypertonia.

Interactions

Concomitant use of tizanidine and moderate or potent CYP1A2 inhibitors is contraindicated. Concomitant use of tizanidine with fluvoxamine, a potent CYP1A2 inhibitor in man, resulted in a 33-fold increase in the tizanidine AUC (plasma drug concentration-time curve) by fluvoxamine.

References

1. ^ Zanaflex for Fibromyalgia
2. ^ http://www.pharmer.org/images/domestic/tizanidine-503

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Agonists: Arbutamine • BAAM • Befunolol • Broxaterol • Buphenine • Cimaterol • Ephedrine • Higenamine • Isoetarine • Isoxsuprine • Mabuterol • Methoxyphenamine • Oxyfedrine • Prenalterol • Pseudoephedrine • Ractopamine • Tretoquinol • Zilpaterol • Zinterol Reuptake Inhibitors Plasmalemmal NET Inhibitors Norepinephrine Reuptake Inhibitors: Atomoxetine (Tomoxetine) • Ciclazindol • Mazindol • Nisoxetine • Reboxetine • Tandamine • Tapentadol • Viloxazine; Norepinephrine-Dopamine Reuptake Inhibitors: Amineptine • Bupropion (Amfebutamone) • Fencamine • Fencamfamine • Lefetamine • LR-5182 • Manifaxine • Methylphenidate • Nomifensine • O-2172 • Radafaxine; Serotonin-Norepinephrine Reuptake Inhibitors: Bicifadine • Desvenlafaxine • Duloxetine • Milnacipran • Sibutramine • Tramadol • Venlafaxine; Serotonin-Norepinephrine-Dopamine Reuptake Inhibitors: Brasofensine • Diclofensine • DOV-102,677 • DOV-21,947 • DOV-216,303 • JNJ-7925476 • JZ-IV-10 • Methylnaphthidate • Naphyrone • NS-2359 • PRC200-SS • SEP-225,289 • SEP-227,162 • Tesofensine; Tricyclic Antidepressants: Amitriptyline • Butriptyline • Cianopramine • Clomipramine • Desipramine • Dosulepin • Doxepin • Imipramine • Lofepramine • Nortriptyline • Protriptyline • Trimipramine; Tetracyclic Antidepressants: Amoxapine • Maprotiline • Mianserin • Oxaprotiline; Others: Cocaine • Nefazodone • Nefopam • Ziprasidone TRPC6 Activators Adhyperforin • Hyperforin Vesicular VMAT Inhibitors Ibogaine • Reserpine • Tetrabenazine Releasing Agents Oxazolines: 4-Methylaminorex (4-MAR, 4-MAX) • Aminorex • Clominorex • Cyclazodone • Fenozolone • Fluminorex • Pemoline • Thozalinone; Phenethylamines (also Amphetamines, Cathinones, Phentermines, etc): 2-Hydroxyphenethylamine (2-OH-PEA) • 4-Methylamphetamine (4-MA) • 4-Methylmethamphetamine (4-MMA) • α-Ethylphenethylamine (α-Et-PEA) • Alfetamine • Amphetamine (Dextroamphetamine, Levoamphetamine) • Amphetaminil • Amfepentorex • β-Methylphenethylamine (β-Me-PEA) • Benzodioxolylbutanamine (BDB) • Benzodioxolylhydroxybutanamine (BOH) • Benzphetamine • Buphedrone • Butylone • Cathine • Cathinone • Clobenzorex • Clortermine • Diethylcathinone (Diethylpropion, Amfepramone) • Dibutylone • Dimethoxyamphetamine (DMA) • Dimethoxymethamphetamine (DMMA) • Dimethylamphetamine • Dimethylcathinone (Dimethylpropion, Metamfepramone) • Ephedrine (EPH) • Ethcathinone (Ethylpropion) • Ethylamphetamine • Ethylbenzodioxolylbutanamine (EBDB) • Ethylone • Fenethylline • Fenproporex • Flephedrone • Fludorex • Furfenorex • Hordenine • Indanorex • Indanylamphetamine (IAP) • Lisdexamfetamine • Lophophine (Homomyristicylamine) • Mefenorex • Mephedrone • Mephentermine • Methamphetamine (Desoxyephedrine, Methedrine; Dextromethamphetamine, Levomethamphetamine) • Methcathinone (Methylpropion) • Methedrone • Methoxymethylenedioxyamphetamine (MMDA) • Methoxymethylenedioxymethamphetamine (MMDMA) • Methylbenzodioxolylbutanamine (MBDB) • Methylenedioxyamphetamine (MDA; Tenamfetamine) • Methylenedioxyethylamphetamine (MDEA) • Methylenedioxyhydroxyamphetamine (MDOH) • Methylenedioxymethamphetamine (MDMA) • Methylenedioxymethylphenethylamine (MDMPEA; Homarylamine) • Methylenedioxyphenethylamine (MDPEA; Homopiperonylamine) • Methylone • Naphthylamphetamine (NAP) • Ortetamine • Oxaflozane • Parabromoamphetamine (PBA) • Parachloroamphetamine (PCA) • Parafluoroamphetamine (PFA) • Parafluoromethamphetamine (PFMA) • Parahydroxyamphetamine (PHA) • Paraiodoamphetamine (PIA) • Paramethoxyamphetamine (PMA) • Paramethoxyethylamphetamine (PMEA) • Paramethoxymethamphetamine (PMMA) • Paredrine (Norpholedrine, Oxamphetamine) • Phendimetrazine • Phenethylamine (PEA) • Phenmetrazine • Pholedrine • Phenpentermine • Phenpromethamine • Phentermine • Phenylpropanolamine (PPA) • Propylamphetamine • Pseudoephedrine (PSE) • Tiflorex (Flutiorex) • Tyramine (TRA) • Xylopropamine • Zylofuramine; Piperazines: 2,5-Dimethoxy-4-bromobenzylpiperazine (2C-B-BZP) • Benzylpiperazine (BZP) • Methoxyphenylpiperazine (MeOPP; Paraperazine) • Methylbenzylpiperazine (MBZP) • Methylenedioxybenzylpiperazine (MDBZP; Piperonylpiperazine) • Parafluorophenylpiperazine (pFPP; Fluoperazine); Others: 2-Aminoindane (2-AI) • 2-Aminotetralin (2-AT) • 2-Benzylpiperidine (2-BP) • 4-Benzylpiperidine (4-BP) • Clofenciclan • Cyclopentamine • Cypenamine • Cyprodenate • Feprosidnine • Gilutensin • Heptaminol • Hexacyclonate • Isometheptene • Methylhexanamine • Octodrine • Phthalimidopropiophenone • Propylhexedrine (PHX) • Tuaminoheptane (Tuamine) Enzyme Inhibitors Anabolism PAH Inhibitors 3,4-Dihydroxystyrene TH Inhibitors 3-Iodotyrosine • Aquayamycin • Bulbocapnine • Metirosine • Oudenone AAAD Inhibitors Benserazide • Carbidopa DBH Inhibitors Disulfiram • Nepicastat • Tropolone PNMT Inhibitors CGS-19281A • SKF-64139 • SKF-7698 Catabolism MAO Inhibitors Nonselective: Iproclozide • Iproniazid • Isocarboxazid • Nialamide • Phenelzine • Pheniprazine • Tranylcypromine; MAO-A Selective: Befloxatone • Brofaromine • Cimoxatone • Clorgiline • Harmala Alkaloids • Minaprine • Moclobemide • Pirlindole • Toloxatone • Tyrima; MAO-B Selective: Lazabemide • Pargyline • Rasagiline • Selegiline * Note that MAO-B inhibitors also influence norepinephrine/epinephrine levels since they inhibit the breakdown of their precursor dopamine. COMT Inhibitors Entacapone • Tolcapone Others Precursors L-Phenylalanine → L-Tyrosine → L-DOPA (Levodopa) → Dopamine • L-DOPS (Droxidopa) Cofactors Ferrous Iron (Fe2+) • S-Adenosyl-L-Methionine • Vitamin B3 (Niacin, Nicotinamide → NADPH) • Vitamin B6 (Pyridoxine, Pyridoxamine, Pyridoxal → Pyridoxal Phosphate) • Vitamin B9 (Folic Acid → Tetrahydrofolic Acid) • Vitamin C (Ascorbic Acid) • Zinc (Zn2+) Others Activity Enhancers: Benzofuranylpropylaminopentane (BPAP) • Phenylpropylaminopentane (PPAP); Release Blockers: Bretylium • Guanethidine

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