What is Zanaflex and how is it used?

Zanaflex is a prescription medicine used to treat the symptoms of muscle stiffness (spasticity) associated with conditions such as Cerebral palsy or other neurological disorders. Zanaflex may be used alone or with other medications.

Zanaflex belongs to a class of drugs called Central Alpha-2-Adrenergic Agonist.

It is not known if Zanaflex is safe and effective in children.

What are the possible side effects of Zanaflex?
Zanaflex may cause serious side effects including:

low blood pressure,
abnormal liver function tests,
excessive drowsiness,
slow heartrate,
dry mouth,
tiredness, and
Get medical help right away, if you have any of the symptoms listed above.

The most common side effects of Zanaflex include:

dry mouth,
urinary tract infection,
abnormal liver function tests,
speech disorder,
lazy eye (amblyopia),
urinary frequency,
flu symptoms,
uncontrolled muscle movements,
sore throat, and
runny nose
Tell the doctor if you have any side effect that bothers you or that does not go away.

These are not all the possible side effects of Zanaflex. For more information, ask your doctor or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Zanaflex® (tizanidine hydrochloride) is a central alpha2-adrenergic agonist. Tizanidine HCl is a white to off-white, fine crystalline powder, which is odorless or with a faint characteristic odor. Tizanidine is slightly soluble in water and methanol; solubility in water decreases as the pH increases. Its chemical name is 5-chloro-4-(2- imidazolin-2-ylamino)-2,1,3-benzothiadiazole monohydrochloride. Tizanidine’s molecular formula is C9H8ClN5S-HCl, its molecular weight is 290.2 and its structural formula is:

ZANAFLEX Capsules® (tizanidine hydrochloride) Structural Formula Illustration
Zanaflex Capsules® are supplied as 2, 4, and 6 mg capsules for oral administration. Zanaflex Capsules® contain the active ingredient, tizanidine hydrochloride (2.29 mg equivalent to 2 mg tizanidine base, 4.58 mg equivalent to 4 mg tizanidine base, and 6.87 mg equivalent to 6 mg tizanidine base), and the inactive ingredients, hypromellose, silicon dioxide, sugar spheres, titanium dioxide, gelatin, and colorants.

Zanaflex® tablets are supplied as 4 mg tablets for oral administration. Zanaflex® tablets contain the active ingredient, tizanidine hydrochloride (4.58 mg equivalent to 4 mg tizanidine base), and the inactive ingredients, colloidal silicon dioxide, stearic acid, microcrystalline cellulose and anhydrous lactose.

source:  rxlist.com/zanaflex-drug.htm#description