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Muscle Spasm Treatment with Flexeril aka Cyclobenzeprine

Flexeril Side Effects, Drug Action and More


Updated June 23, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Muscle spasm treatment can range from massage and stretching on the holistic side to drugs on the conventional medical side.  To help loosen up muscle spasm, some people take Flexeril (also known as Cyclobenzeprine). This drug is one type of skeletal muscle relaxer.  Here is a rundown on Flexeril, including side effects, generic information, dosage and storage information, and more.

Related:  Types of Skeletal Muscle Relaxers

Brand Name :

Flexeril. By prescription only.

Generic Name:

Cyclobenzeprine. Cyclobenzeprine is available in generic form, by prescription only.

Class and Drug Action:

Skeletal Muscle Relaxant. Cyclobenzeprine works in the central nervous system to relieve skeletal muscle spasm throughout the body. It is not effective, however, for conditions involving the nervous system, such as multiple sclerosis. Cyclobenzeprine is used short-term, in conjunction with physical therapy and rest for acute cases of muscle injury, for example sprains and strains.


Appropriate Usage:

Duration of use should be no longer than 2-3 weeks. Cyclobenzeprine is taken by mouth up to 3 times per day, unless otherwise prescribed by your doctor. DO NOT INCREASE YOUR DOSAGE! If you miss a dose, and it is now closer the time of the next dose, just resume taking the medication with the next scheduled time. Do not double dose to make up for a missed dosage.


Store cyclobenzaprine at room temperature or as directed by your pharmacist.

Side Effects:

The most common side effects include:

  • dry mouth
  • drowsiness
  • dizziness
  • tiredness
  • constipation
  • blurred vision
  • unplesant taste
  • nervousness
  • confusion
  • abdominal pain or discomfort


More Serious Side Effects:

Serious side effects are rare, but if these do occur they require prompt medical attention 2:

  • 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



The elderly will be more sensitive to the side effects associated with this disease. Pregnant women should use only when absolutely necessary; the drug might pass on to the breast milk.

Because side effects include dizziness and drowsiness, exercise caution when deciding to drive a car or operate machinery. Alcohol will amplify these side effects, and is best limited, to prevent injury or accident.


More Precautions - Drug Interactions:


Communicating with your Doctor is key. Always tell your doctor about the following:

  • allergies, especially to Flexeril
  • overactive thyroid
  • arrhythmia
  • any other heart problems including congestive heart failure, heart block or conduction disorders
  • recent heart attack
  • liver disease
  • urinary retention
  • glaucoma

Certain types of other medications (asthma, weight loss, stimulants, drugs that cause drowsiness and tricyclic antidepressants, to name a few) may cause drug interaction problems. Tell your doctor EVERYTHING you are taking. For more information use the Drug Finder.

Related:  Choose and Effective Pain Medication

1 Cyclobenzeprine Oral. Rx Patient Drug Information from First DataBank 6.8.05. Rx List, The Internet Drug Index. Retrieved from: http://www.rxlist.com/drugs/drug-11372-Flexeril+Oral.aspx?drugid=11372&drugname=Flexeril+Oral January 30, 2006.

2 MedicineNet. 5.11.98. Retrieved from: http://www.medicinenet.com/cyclobenzaprine/article.htm January 30, 2006.

3. Malanga, Gerard, MD. Muscle Relaxants in the Treatment of Acute Low Back Pain, Types of Muscle Relaxing Medication: Part 4. Spine Universe. Retrieved from: http://www.spineuniverse.com/displayarticle.php/article1833.html. January 29, 2006.

Date Created: January 30, 2006.


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