An Introduction to Zanaflex Side Effects
As with any medicine, side effects are possible with
Zanaflex® (
tizanidine hydrochloride). However, not everyone who takes the medication will have problems. In fact, most people tolerate it quite well. If side effects do occur, in most cases, they are minor and either require no treatment or are treated easily by you or your healthcare provider.
(This article covers many, but not all, of the possible side effects with this medication. Your healthcare provider can discuss a more complete list of Zanaflex side effects with you.)
Common Side Effects of Zanaflex
Zanaflex has been studied extensively in clinical trials. In these studies, side effects occurring in the group of people taking Zanaflex were documented and compared to those that occurred in a similar group of people taking a placebo (a "sugar pill" with no active ingredients).
Based on these studies, the most common side effects of Zanaflex tablets included:
- Drowsiness -- in up to 92 percent of people
- Dry mouth -- up to 88 percent of people (see Zanaflex and Dry Mouth)
- Weakness, fatigue, or tiredness -- up to 78 percent
- Dizziness -- up to 45 percent
- Low blood pressure (hypotension) -- up to 33 percent
- A slow heart rate (bradycardia) -- up to 10 percent
- Urinary tract infection (UTI), such as a bladder infection -- up to 10 percent.
Other common reactions (occurring in 3 to 6 percent of people) included:
- Infection
- Constipation
- Increased liver enzymes (found using a blood test)
- Vomiting
- Speech problems
- Blurred vision
- Frequent urination
- Flu symptoms (such as a fever and chills)
- Nervousness
- Sore throat
- Runny or stuffy nose
- Abnormal, involuntary muscle movements.
