Pain Home > Side Effects of Cyclobenzaprine ER
Dry mouth, constipation, dizziness, and nausea are some of the most commonly reported side effects of cyclobenzaprine ER. Other, less-common side effects (occurring in less than 1 percent of people using the muscle relaxant) include loss of appetite, insomnia, and gas. While most cyclobenzaprine ER side effects are minor, some are potentially serious and require immediate medical attention, including fainting, difficulty urinating, or seizures.
As with any medicine, side effects are possible with cyclobenzaprine ER (Amrix®). 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 can easily be treated by you or your healthcare provider.
(This article covers many, but not all, of the possible side effects with cyclobenzaprine ER. Your healthcare provider can discuss a more complete list of cyclobenzaprine ER side effects with you.)
There are a number of side effects with cyclobenzaprine ER that you should report to your healthcare provider. These include, but are not limited to:
- A rapid heart rate (tachycardia)
- An irregular heart rhythm (arrhythmia)
- Feelings of a rapidly or forcefully beating heart (known as heart palpitations)
- Low blood pressure (hypotension)
- Signs of liver damage, including yellow eyes or skin (jaundice), dark urine, and upper right abdominal pain
- Anxiety, agitation, or psychotic behavior
- Difficulty passing urine
- Signs of an allergic reaction, including unexplained rash, hives, itching, unexplained swelling, wheezing, or difficulty breathing or swallowing.