Tizanidine

Brand names: Zanaflex®

Chemical formula:

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

Espa�ol:
• Tizanidina Clorhidrato, Cápsula oral
• Tizanidina Clorhidrato, Tableta oral

Tizanidine Hydrochloride Oral capsule

What is this medicine?

TIZANIDINE (tye ZAN i deen) 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.

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Tizanidine

Systematic (IUPAC) name
5-chloro-N-(4,5-dihydro-1H-imidazol-2-yl)benzo[c][1,2,5]thiadiazol-4-amine
Clinical data
Trade names	Zanaflex
AHFS/Drugs.com	monograph
MedlinePlus	a601121
Pregnancy cat.	?
Legal status	℞-only (US)
Routes	Oral, Intranasal, Injection
Pharmacokinetic data
Protein binding	30%
Metabolism	CYP 1A2
Half-life	2.54 hours
Identifiers
CAS number	51322-75-9
ATC code	M03BX02
PubChem	CID 5487
DrugBank	APRD00128
ChemSpider	5287 Y
UNII	6AI06C00GW Y
KEGG	D08611 Y
ChEMBL	CHEMBL1079 Y
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
Chemical data
Formula	C9H8ClN5S
Mol. mass	253.712 g/mol
SMILES	eMolecules & PubChem
InChI 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) Y Key:XFYDIVBRZNQMJC-UHFFFAOYSA-N Y
Y(what is this?)  (verify)

Tizanidine (trade names Zanaflex, Sirdalud) is a drug that is used as a muscle relaxant. It is a centrally acting α₂ 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 has been found to be as effective as other antispasmodic drugs and have superior tolerability than baclofen and diazepam.^[2] 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.

Tizanidine can occasionally cause liver damage, generally the hepatocellular type. Clinical trials show that up to 5% of patients treated with tizanidine had elevated liver function test values, though symptoms disappeared upon withdrawal of the drug. Care should be used when first beginning treatment with tizanidine with regular liver tests for the first 6 months of treatment.

Contents 1 Availability 2 Interactions 3 Side effects 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^[3]. Also somewhat common is a white round tablet that is X-scored with what appears to be, on the opposite side, an uppercase "A" with a horizontal line through the right half of the letter, somewhat like a "G" and the numbers 594.^[4] It is also found as a round white tablet with 2 scores on the back which create an X and the letters R L on the other side. This is certainly a 4mg tablet and could also be a 2mg.

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.

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.^{[citation needed]} Tizanidine is a potent sedative. It therefore has the potential, to interact with other CNS depressants. Alcohol should obviously be avoided, particularly as it can cause stomach upset.

It has a Volume of Distribution of 2.6L/Kg (Manufacturers notes).

Side effects

Side effects include drowsiness, dry mouth with increased dosage, dizziness, increased visual acuity. It also causes vivid dreams when taken at bedtime.

References

1. ^ Zanaflex for Fibromyalgia
2. ^ Kamen, L.; Henney, HR.; Runyan, JD. (Feb 2008). "A practical overview of tizanidine use for spasticity secondary to multiple sclerosis, stroke, and spinal cord injury.". Curr Med Res Opin 24 (2): 425–39. doi:10.1185/030079908X261113. PMID 18167175. 
3. ^ http://www.pharmer.org/images/domestic/tizanidine-503
4. ^ http://www.drugs.com/tizanidine-images.html

v · d · eSkeletal muscle relaxants (M03) Peripherally acting (primarily antinicotinic, NMJ block) Non-depolarizing Curare alkaloids Alcuronium • Dimethyltubocurarine • Tubocurarine 4° ammonium agents ultra-short duration: Gantacurium short duration: Mivacurium  • Chandonium intermediate duration: Atracurium  • Cisatracurium  • Fazadinium  • Rocuronium  • Vecuronium long duration: Doxacurium • Dimethyltubocurarine • Pancuronium • Pipecuronium  • Laudexium  • Gallamine unsorted: Hexafluronium (Hexafluorenium) Depolarizing Choline derivatives: Suxamethonium (Succinylcholine) Polyalkylene derivatives: Hexamethonium ACh release inhibitors Botulinum toxin Centrally acting Carbamic acid esters Carisoprodol • Cyclarbamate • Difebarbamate • Febarbamate • Meprobamate • Methocarbamol • Phenprobamate • Styramate • Tybamate Benzodiazepines Bentazepam • Diazepam • Lorazepam • Nitrazepam • Tetrazepam Anticholinergics (Antimuscarinics) Cyclobenzaprine • Orphenadrine Other Baclofen • Chlormezanone • Chlorphenesin • Chlorzoxazone • Donepezil • Eperisone • Flopropione • Mephenesin • Mephenoxalone • Metaxalone • Phenyramidol • Pridinol • Promoxolane • Quinine • Thiocolchicoside • Tizanidine • Tolperisone • Trazodone Directly acting Dantrolene M: MUS, DF+DRCT anat (h/n, u, t/d, a/p, l)/phys/devp/hist noco(m, s, c)/cong(d)/tumr, sysi/epon, injr proc, drug (M1A/3)

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COMT 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: BPAP • PPAP; Release blockers: Bethanidine • Bretylium • Guanadrel • Guanazodine • Guanclofine • Guanethidine • Guanoxan; Toxins: Oxidopamine (6-Hydroxydopamine) List of adrenergic drugs

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