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Dynamic Chiropractic – July 1, 2009, Vol. 27, Issue 14

Alternatives to Flexeril (Cyclobenzaprine hydrochloride)

By Daniel Hough, DC

Flexeril is prescribed for the relief of muscle spasm. It is in a class of drugs called spasmolytics. It acts on the central nervous system rather than the muscles, per se - it is a central-nervous-system depressant.

Flexeril is manufactured by Merck and Co., Inc., the third largest pharmaceutical company in the world. Merck's total 2006 sales were more than $22.5 billion.1 Price Rite Drug in Bozeman, Mont., where I practice, charges $10.60 for 30 tablets (10 mg each) of the generic equivalent of Flexeril, which is a 10-day supply.

Problems With Flexeril

In his book Best Pills Worst Pills, written in collaboration with the AARP, Dr. Sidney Wolfe advises against the use of cyclobenzaprine.2 He states, " Cyclobenzaprine has not been shown to be any more effective than painkillers or anti-inflammatory drugs such as aspirin for relieving the pain of local muscle spasm." He further advises that Flexeril is structurally similar to tricyclic antidepressants and may cause some of the same dangerous side effects, particularly in older patients. It is also addictive.2

My PDR lists more than 65 adverse side effects for Flexeril, including dizziness, abnormal heartbeat, aggressive behavior, agitation, confusion, convulsions, hallucinations, headache, hepatitis, muscle twitching and severe allergic reactions.3

Localized muscle spasm is predominantly caused by spinal cord reflexes resulting from pain.4 Pain stimuli arising from muscles can be caused by muscle damage (strain), severe cold, metabolic abnormalities, inflammation and dysfunction of the joint moved by those muscles. Hilton's Law states that a joint is innervated by the same nerve trunk that innervates the muscles which move the joint.

Safer Alternatives

Skullcap and valarian root are anti-spasmodic herbs.5 Bromelain taken between meals and eicosapentaenoic acid (fish oil) are good natural anti-inflammatories.6 Ice and massage are also beneficial in reducing muscle spasm and inflammation.

Chiropractic adjustment relieves muscle spasm by addressing the cause. There are chiropractors who will not attempt to adjust an acute subluxation, and I have patients who have been told by their medical doctor to wait until the muscle spasm subsides to be adjusted. The sooner you adjust a subluxated joint, the better. No health care provider would advocate that a dislocated shoulder be left dislocated until the muscle spasm stops. Reduce the shoulder and the spasm stops. Adjust the dysfunctional joint and the local muscle spasm stops.


  1. Fortune 500 company rankings. Fortune Magazine, 2007.
  2. Wolfe, SM. Worst Pills Best Pills. Washington, D.C.: Public Citizen Health Research Group, 1988, p. 516.
  3. Sifton DW, et al., eds. The PDR Pocket Guide to Prescription Drugs. New York: Simon and Schuster.
  4. Guyton AD. Textbook of Medical Physiology. New York: WB Saunders, 1986, p. 617.
  5. Lust J. The Herb Book. Benedict Lust Publications, 1974, pp. 200, 416
  6. Murray MP, Pizzorno JE. Encyclopedia of Natural Medicine. Rocklin, Calif: Prima Publishing.

Dr. Daniel Hough is a 1991 graduate of Western States Chiropractic College. A former member of the Montana Chiropractic Association Ethics Committee, he practices in Bozeman, Mont.

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