Tizanidine Hydrochloride

Indications
It is used in the symptomatic treatment of painful muscle spasm associated with musculoskeletal conditions and as an adjunct in the management of spasticity associated with multiple sclerosis or spinal cord disorders.

Therapeutic Class
Centrally acting Skeletal Muscle Relaxants

Pharmacology
Tizanidine is a short-acting drug for the management of spasticity. Tizanidine is an agonist at α2-adrenergic receptor sites and presumably reduces spasticity by increasing presynaptic inhibition of motor neurons. In animal models, tizanidine has no direct effect on skeletal muscle fibers or the neuromuscular junction, and no major effect on monosynaptic spinal reflexes. The effects of tizanidine are greatest on polysynaptic pathways. The overall effect of these actions is thought to reduce facilitation of spinal motor neurons.

Dosage & Administration
The usual initial daily dose is 2 mg as a single dose. The daily dose may be increased thereafter according to response in steps of 2 mg at intervals of at least 3 to 4 days, usually up to 24 mg daily given in 3 to 4 divided doses. The maximum recommended dose is 36 mg daily.

Interaction
Alcohol or other CNS depressants may enhance the CNS effects of Tizanidine. There may be an additive hypotensive effect when Tizanidine is used in patients receiving antihypertensive therapy.

Contraindications
Tizanidine Hydrochloride is contraindicated to the patients who have known hypersensitivity to this drug and in case of severe hepatic impairment.

Side Effects
Tizanidine Hydrochloride may cause drowsiness, fatigue, dizziness, dry mouth, nausea, gastrointestinal disturbances, hypotension. Bradycardia, insomnia, hallucinations and altered liver enzymes, and rarely acute hepatitis have also been reported.

Pregnancy & Lactation
Tizanidine has no teratogenic effects in rats and rabbits. As there have been no controlled studies in pregnant women, it should not be used during pregnancy unless the benefit clearly outweighs the risk. Although only small amounts of Tizanidine are excreted in animal milk, lactating women should not take Tizanidine.

Precautions & Warnings
Patients with impaired kidney or liver function; when patients drive a vehicle or operate machinery.

Use in Special Populations
Children: Experience in children is limited and the use of Tizanidine in this patient group is not recommended.
Elderly: Renal clearance in the elderly may in some cases be significantly decreased. Caution is therefore indicated when using in elderly patients.

Storage Conditions
Store in a cool & dry place, protected from light & moisture. Do not freeze. Keep all medicines out of the reach of children.