Zanaflex
Hands-On Treatment May Help Low Back Pain »
"Medscape Medical News
March 19, 2013 -- People with low back pain may benefit from a hands-on treatment known as osteopathic manual therapy (OMT) more than they do from ultrasound therapy.
A new study suggests that OMT leads t"...
Read the Hands-On Treatment May Help Low Back Pain article »
Zanaflex
Zanaflex Capsules™
(tizanidine hydrochloride)
Zanaflex® Tablets
(tizanidine hydrochloride)
PHARMACOKINETIC DIFFERENCES BETWEEN Zanaflex Capsules™ (tizanidine) AND ZANAFLEX (tizanidine) ® TABLETS:
Zanaflex Capsules™ (tizanidine) ARE NOT BIOEQUIVALENT TO ZANAFLEX (tizanidine) ® TABLETS IN THE FED STATE. THE PRESCRIBER SHOULD BE THOROUGHLY FAMILIAR WITH THE COMPLEX EFFECTS OF FOOD ON TIZANIDINE PHARMACOKINETICS (see PHARMACOKINETICS and DOSAGE AND ADMINISTRATION).
DRUG DESCRIPTION
Zanaflex® (tizanidine hydrochloride) is a centrally acting α2-adrenergic agonist. Tizanidine HCl (tizanidine) 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-benzothiodiazole hydrochloride. Tizanidine's molecular formula is C9H8CIN5 S-HCl, its molecular weight is 290.2 and its structural formula is:
![]() |
Zanaflex Capsules™ (tizanidine) are supplied as 2, 4, and 6 mg capsules and Zanaflex (tizanidine) ®
tablets are supplied as 2 and 4 mg tablets for oral administration. Zanaflex (tizanidine) Capsules™ are composed of 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,
hydroxypropyl methyl cellulose, silicon dioxide, sugar spheres, titanium dioxide,
gelatin, and colorants.
Zanaflex (tizanidine) ® tablets are composed of the active ingredient, tizanidine hydrochloride (2.29 mg equivalent to 2 mg tizanidine base and 4.58 mg equivalent to 4 mg tizanidine base), and the inactive ingredients, silicon dioxide colloidal, stearic acid, microcrystalline cellulose and anhydrous lactose.
What are the possible side effects of tizanidine (Zanaflex)?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
- feeling light-headed, fainting, slow heart rate;
- hallucinations, confusion, unusual thoughts or behavior;
- nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
- burning or pain when you urinate.
Less serious side effects may be more...
Read All Potential Side Effects and See Pictures of Zanaflex »
What are the precautions when taking tizanidine (Zanaflex)?
Before taking tizanidine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: low blood pressure, kidney disease, liver disease.
This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Avoid alcoholic beverages.
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal...
Last reviewed on RxList: 10/4/2010
This monograph has been modified to include the generic and brand name in many instances.
Additional Zanaflex Information
Zanaflex - User Reviews
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Chronic Pain/Back Pain
Find tips and advances in treatment.







