cyclobenzaprine (Flexeril, Amrix, Fexmid)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

Is cyclobenzaprine (Amrix, Fexmid) available as a generic drug?


Do I need a prescription for cyclobenzaprine (Amrix, Fexmid)?


Why is cyclobenzaprine (Amrix, Fexmid) prescribed to patients?

  • Cyclobenzaprine is used with rest and physical therapy for short-term relief of muscle spasms associated with acute painful muscle and skeletal conditions. It is only for short-term use, up to two or three weeks.

What are the side effects of cyclobenzaprine (Amrix, Fexmid)?

The most common side effects of cyclobenzaprine include:

Other reported side effects include:

Possible serious side effects include:

Abrupt cessation after prolonged therapy may cause withdrawal symptoms such as headaches, nausea, and weakness.

What is the dosage for cyclobenzaprine (Amrix, Fexmid)?

  • The recommended dose of cyclobenzaprine dose is 5 or 10 mg three times daily using immediate release tablets or 15 or 30 mg once daily using extended release tablets.

Which drugs or supplements interact with cyclobenzaprine (Amrix, Fexmid)?

Is cyclobenzaprine (Amrix, Fexmid) safe to use during pregnancy or while breastfeeding?

  • There are no adequate studies of cyclobenzaprine in pregnant women. However, studies in animals suggest no important effects on the fetus. Cyclobenzaprine therefore can be used in pregnancy if the physician feels that it is necessary.
  • It is not known whether cyclobenzaprine is secreted in milk. However, since it is related to the tricyclic antidepressants, some of which are excreted in breast milk, caution is advised in using this medication in women who are breastfeeding.

What else should I know about cyclobenzaprine (Amrix, Fexmid)?

What preparations of cyclobenzaprine (Amrix, Fexmid) are available?
  • Tablets: 5 and 10 mg.
  • Capsules (Extended Release): 15 and 30 mg.
How should I keep cyclobenzaprine (Amrix, Fexmid) stored?
  • Tablets should be stored between 15 C and 30 C (59 F and 86 F).
How does cyclobenzaprine (Amrix, Fexmid) work?
  • Cyclobenzaprine relieves muscle spasm when the spasm is due to local problems, that is, in the muscle itself and not in the nerves controlling the muscles. Cyclobenzaprine has no effect on muscle function. Cyclobenzaprine seems to accomplish its beneficial effect through a complex mechanism within the nervous system, probably in the brainstem.
When was cyclobenzaprine (Amrix, Fexmid) approved by the FDA?
  • The FDA approved cyclobenzaprine in August 1977.

Reference: FDA Prescribing Information

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Cyclobenzaprine (Fexmid, Amrix) is a drug prescribed for the short-term relief of muscle spasms associated with acute painful muscle and skeletal conditions. Common side effects include:

Possible serious side effects include:

Drug interactions, warnings and precautions, and pregnancy and breastfeeding safety information should be reviewed prior to taking any medication. The brand name Flexeril has been discontinued and is no longer available in the US.

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Reviewed on 11/11/2016
Reference: FDA Prescribing Information

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