zanaflex

Recommended starting dose: 2 mg; dose can be repeated at 6 to 8 hour intervals, up to a maximum of 3 doses in 24 hours ( 2.1 ) 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 ( 2.1 ) 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 ( 2.1 , 12.3 ) To discontinue Zanaflex, decrease dose slowly to minimize the risk of withdrawal and rebound hypertension, tachycardia, and hypertonia ( 2.2 ) 2.1 Dosing Information Zanaflex Capsules ® or Zanaflex ® tablets may be prescribed with or without food. Once the formulation has been selected and the decision to take with or without food has been made, this regimen should not be altered. Food has complex effects on tizanidine pharmacokinetics, which differ with the different formulations. Zanaflex Capsules and Zanaflex tablets are bioequivalent to each other under fasting conditions (more than 3 hours after a meal), but not under fed conditions (within 30 minutes of a meal). These pharmacokinetic differences may result in clinically significant differences when switching administration of tablet and capsules and when switching administration between the fed or fasted state. These changes may result in increased adverse events, or…

The following adverse reactions are described elsewhere in other sections of the prescribing information: Hypotension [see Warnings and Precautions ( 5.1 )] Liver Injury [see Warnings and Precautions ( 5.2 )] Sedation [see Warnings and Precautions ( 5.3 )] Hallucinosis/Psychotic-Like Symptoms [see Warnings and Precautions ( 5.4 )] Hypersensitivity Reactions [see Warnings and Precautions ( 5.6 )] The most common adverse reactions (greater than 2% of 264 patients taking tizanidine and greater than in placebo-treated patients in three multiple dose, placebo-controlled studies) were dry mouth, somnolence, asthenia, dizziness, urinary tract infection, constipation, liver function tests abnormal, vomiting, speech disorder, amblyopia, urinary frequency, flu syndrome, SGPT/ALT increased, dyskinesia, nervousness, pharyngitis, and rhinitis ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Covis Pharma at 1-866-488-4423 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in clinical practice. Three double-blind, randomized, placebo-controlled clinical studies were conducted to evaluate the effect of…

Zanaflex is contraindicated in patients taking potent inhibitors of CYP1A2, such as fluvoxamine or ciprofloxacin [see Drug Interactions ( 7.1 , 7.2 )] . Concomitant use with potent inhibitors of CYP1A2, such as fluvoxamine or ciprofloxacin ( 4 , 5.5 , 7.1 , 7.2 )

A review of the safety surveillance database revealed cases of intentional and accidental Zanaflex overdose. Some of the cases resulted in fatality and many of the intentional overdoses were with multiple drugs including CNS depressants. The clinical manifestations of tizanidine overdose were consistent with its known pharmacology. In the majority of cases a decrease in sensorium was observed including lethargy, somnolence, confusion and coma. Depressed cardiac function is also observed including most often bradycardia and hypotension. Respiratory depression is another common feature of tizanidine overdose. Should overdose occur, basic steps to ensure the adequacy of an airway and the monitoring of cardiovascular and respiratory systems should be undertaken. Tizanidine is a lipid-soluble drug, which is only slightly soluble in water and methanol. Therefore, dialysis is not likely to be an efficient method of removing drug from the body. In general, symptoms resolve within one to three days following discontinuation of tizanidine and administration of appropriate therapy. Due to the similar mechanism of action, symptoms and management of tizanidine overdose are similar to that following clonidine overdose. For the most recent information concerning the management of overdose, contact a poison control center.

U.S. Poison Control: call or text 1-800-222-1222 (free, 24/7). In an emergency call 911. From the FDA label; not medical advice.

7.1 Fluvoxamine Concomitant use of fluvoxamine and Zanaflex is contraindicated. Changes in pharmacokinetics of tizanidine when administered with fluvoxamine resulted in significantly decreased blood pressure, increased drowsiness, and increased psychomotor impairment [see Contraindications ( 4 ) and Clinical Pharmacology ( 12.3 )] . 7.2 Ciprofloxacin Concomitant use of ciprofloxacin and Zanaflex is contraindicated. Changes in pharmacokinetics of tizanidine when administered with ciprofloxacin resulted in significantly decreased blood pressure, increased drowsiness, and increased psychomotor impairment [see Contraindications ( 4 ) and Clinical Pharmacology ( 12.3 )] . 7.3 CYP1A2 Inhibitors other than Fluvoxamine and Ciprofloxacin Because of potential drug interactions, concomitant use of Zanaflex with other CYP1A2 inhibitors, such as zileuton, fluoroquinolones other than strong CYP1A2 inhibitors (which are contraindicated), antiarrhythmics (amiodarone, mexiletine, propafenone, and verapamil), cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine) should be avoided. If their use is clinically necessary, therapy should be initiated with 2 mg dose and increased in 2–4 mg steps daily based on patient response to therapy. If adverse reactions such as hypotension, bradycardia, or excessive drowsiness occur, reduce or discontinue Zanaflex therapy [see Warnings and Precautions ( 5.5 ) and Clinical Pharmacology ( 12.3 )] . 7.4 Oral Contraceptives Concomitant use of Zanaflex with oral contraceptives is not recommended. However, if concomitant use is clinically necessary, initiate Zanaflex with a single 2 mg dose and increase in 2–4 mg steps daily based on patient response to therapy. If adverse reactions such as hypotension, bradycardia, or excessive drowsiness occur, reduce or discontinue Zanaflex therapy [see Clinical Pharmacology ( 12.3 )] . 7.5 Alcohol Alcohol increases the overall amount of drug in the bloodstream after a dose of Zanaflex. This was associated with an increase in adverse reactions of Zanaflex. The CNS depressant effects of Zanaflex and alcohol are additive [see Clinical Pharmacology ( 12.3 )] . 7.6 Other CNS Depressants The sedative effects of Zanaflex with CNS depressants (e.g., benzodiazepines, opioids, tricyclic antidepressants) may be additive. Monitor patients who take Zanaflex with another CNS depressant for symptoms of excess sedation [see Clinical Pharmacology ( 12.3 )] . 7.7 α 2 -Adrenergic Agonists Because hypotensive effects may be cumulative, it is not recommended that Zanaflex be used with other α 2 -adrenergic agonists [see Warnings and Precautions ( 5.1 )] .