Currently Enrolling Trials
Zanaflex (tizanidine hydrochloride) is a central alpha-2-adrenergic agonist.
Zanaflex is specifically indicated for the management of spasticity. Because of the short duration of therapeutic effect, treatment with Zanaflex should be reserved for those daily activities and times when relief of spasticity is most important.
Zanaflex is supplied as a capsule and a tablet. The recommended starting dose is 2 mg; dose can be repeated at 6 to 8 hour intervals, up to a maximum of 3 doses in 24 hours. Dosage can be increased by 2 mg to 4 mg per dose, with 1 to 4 days between increases; total daily dose should not exceed 36 mg.
Tizanidine pharmacokinetics differs between tablets and capsules, and when taken with or without food. These differences could result in a change in tolerability and control of symptoms.
To discontinue Zanaflex, decrease dose slowly to minimize the risk of withdrawal and rebound hypertension, tachycardia, and hypertonia
Mechanism of Action
Zanaflex (tizanidine hydrochloride) is a central alpha-2-adrenergic agonist. It presumably reduces spasticity by increasing presynaptic inhibition of motor neurons. The effects of tizanidine are greatest on polysynaptic pathways. The overall effect of these actions is thought to reduce facilitation of spinal motor neurons.
Adverse effects associated with the use of Zanafelx may include, but are not limited to, the following:
- dry mouth
- urinary tract infection
- liver function tests abnormal
- speech disorder
- urinary frequency
- flu syndrome
- SGPT/ALT increased
Clinical Trial Results
In double-blind, placebo-controlled clinical studies Zanaflex was shown to provide significant relief of spasticity symptoms without causing muscle weakness, which can leave patients unable to perform normal daily activities. Additionally, reported side effects did not include evidence of withdrawal effects. Both weakness and potential withdrawal effects can be characteristic of certain currently approved treatment regimens.