Acorda Therapeutics, Inc. the makers of Zanaflex Capsules® (tizanidine hydrochloride), would like to inform you of important safety information regarding Zanaflex Capsules® and Zanaflex® (tizanidine hydrochloride) tablets.
Zanaflex Capsules® (tizanidine hydrochloride) are a short-acting drug indicated for the management of spasticity. Because of the short duration of effect, treatment with Zanaflex Capsules® (tizanidine hydrochloride) should be reserved for those daily activities and times when relief of spasticity is most important.
SAFETY INFORMATION
Zanaflex Capsules® (tizanidine hydrochloride) may cause side effects in some people, including the following:
- Use with fluvoxamine or ciprofloxacin is contraindicted and results in significant increases in tizanidine plasma levels.
- There is a limited database for chronic use of single doses above 8 mg and multiple doses above 24 mg per day.
- Tizanidine is an alpha2-adrenergic agonist and can produce hypotension. In a single-dose study where patients were not titrated, two-thirds of patients given 8 mg of Zanaflex experienced hypotension, which may be minimized by titration of dose. The hypotensive effect is dose related and has been measured following single doses of 2 mg or more.
- Tizanidine occasionally causes liver injury, most often of the hepatocellular type.
- Patients should be advised that sedation may interfere with daily activities. These effects appear to be dose related.
- Visual hallucinatioins or delusion occurred in 3% (5/170) of study patients in two North American clinical trials.
- Use with caution in hepatic or renally impaired patients.
- Use with oral contraceptives results in 50% decrease in tizanidine clearance.
- To discontinue therapy, taper the dose in patients receiving high doses over long time periods to reduce the risk of hypertension, tachycardia and hypertonia.
- In vitro studies indicate that neither tizanidine nor the major metabolites are likely to affect the metabolism of other drugs metabolized by cytochrome P450 isoenzymes.
- Most common adverse events with tizanidine include dry mouth (49%), somnolence (48%), asthenia (weakness, fatigue and/or tiredness) (41%),dizziness (16%) and increased ALT (5%). Other adverse events include UTI, infection and constipation.
- Food has complex effects on tizanidine pharmacokinetics, which differ for the different formulations. These pharmacokinetic differences may result in clinically significant differences when switching formulations, or changing administration during a fed or fasted state. These changes may result in increased adverse events or a delayed/more rapid onset of activity, depending on the nature of the switch.
If you have any questions regarding Zanaflex Capsules® (tizanidine hydrochloride) or Zanaflex tablets, please contact the Acorda Medical Information System at 1-800-367-5109.