Back & Neck Pain Treatment How the Skeletal Muscle Relaxer Flexeril Works By Anne Asher, CPT facebook linkedin Anne Asher, ACE-certified personal trainer, health coach, and orthopedic exercise specialist, is a back and neck pain expert. Learn about our editorial process Anne Asher, CPT Medically reviewed by Medically reviewed by Jonathan Cluett, MD on July 08, 2020 twitter linkedin Jonathan Cluett, MD, is board-certified in orthopedic surgery. He served as assistant team physician to Chivas USA (Major League Soccer) and the United States men's and women's national soccer teams. Learn about our Medical Review Board Jonathan Cluett, MD on July 08, 2020 Print Muscle spasm treatment can range from massage and stretching on the holistic side to drugs on the conventional medical side. To help release very tight muscle spasms, some people take a medication called Flexeril. Approved by the FDA in 1977, this drug is just one type of skeletal muscle relaxers on the market. Below is a fact sheet about Flexeril, including side effects, generic information, dosage and storage information, and more. Tom Merton / OJO Images / Getty Images Names Flexeril is the brand name for cyclobenzaprine. Cyclobenzaprine is the active ingredient and the generic form of the drug. Either way, this medication is available by prescription only. Action Flexeril is sometimes used short-term, in conjunction with physical therapy and rest for acute cases of muscle injury, for example, sprains and strains. By relaxing ultra-tight muscles, it may help you make faster progress with your home exercise program. As a skeletal muscle relaxer, cyclobenzaprine works in the central nervous system, indirectly influencing motor neurons of the brainstem and spinal cord to relieve spasms. Administration and Dosage As with any medication, Flexeril or cyclobenzaprine should be taken according to your doctor's or pharmacist's instructions. It's meant to be used for about 2 to 3 weeks, i.e. not for the long term. Generally, Flexeril or cyclobenzaprine is taken three times per day in tablet form. Immediate-release tablets contain 5 or 10 mg, while extended-release tablets contain 15 or 30 mg. Don't take it upon yourself to increase your dosage. If you feel you need more, speak to your doctor. If you miss a dose and it is now closer to the time of the next dose, resume taking the medication at the next scheduled time. Do not double dose to make up for a missed dosage. Storage Store cyclobenzaprine/Flexeril at room temperature or as instructed by the pharmacist. Side Effects, Complications, and Precautions While a number of potential side effects and complications for taking Flexeril exist, one of the most important is the potential for drowsiness or dizziness. Don't drive or operate machinery or do anything that requires you to be alert while you're under the influence of Flexeril. Avoid alcohol, as well. Some of the most common side effects include but are not limited to: Dry mouth Drowsiness Dizziness Tiredness Constipation Blurred vision Unpleasant taste Nervousness Confusion Abdominal pain or discomfort Serious side effects are rare, but if these do occur they require prompt medical attention. These include, but are not limited to: Mental and mood changes, for example, hallucinations and confusion Difficulty in urinating Dark urine Fast, pounding and/or irregular heartbeat Fainting Yellowing of the eyes and/or skin Stomach and/or abdominal pain Persistent nausea, vomiting and/or lack of appetite Seizures Loss of coordination Note that the elderly will be more sensitive to side effects associated with this medication, and pregnant women should use Flexeril/cyclobenzaprine only if directed by their doctor. The drug may also pass into breast milk. Cyclobenzaprine may contain inactive ingredients that sometimes cause allergic reactions. Be sure to talk with your doctor and pharmacist about this before taking this drug. You also should be transparent about any liver disease, thyroid problems, heart problems, glaucoma and/or difficulty urinating you've had in the past. This way, your healthcare provider can determine if you are at risk for a complication. The same is true for other medications you may be taking. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. U.S. Food and Drug Administration. FLEXERIL® (CYCLOBENZAPRINE HCL) TABLETS. Updated April 2013.