Why Was Flexeril Discontinued?

Reviewed by
Jennifer Houston

Flexeril (cyclobenzaprine), a popular muscle relaxant, was a common treatment for musculoskeletal pain. Its discontinuation in 2023 left many patients searching for answers and alternatives. This article explores the reasons behind Flexeril’s discontinuation, addressing concerns about its side effects, potential for misuse, and available alternatives.

What Was Flexeril?

Flexeril was a brand name for the prescription drug cyclobenzaprine. It was prescribed, often in conjunction with rest and physical therapy, to treat muscle spasms associated with injuries like sprains, fractures, and overuse. Flexeril works by affecting the central nervous system, reducing pain signals sent to the brain, which helps relax muscles without significantly limiting movement. While initially marketed as less likely to cause drowsiness than other muscle relaxants, this claim wasn’t entirely accurate.

Flexeril was also used off-label for conditions such as fibromyalgia (for sleep management), temporomandibular disorders (TMD) (for pain relief and sleep improvement), and post-traumatic stress disorder (PTSD) (for symptom reduction and sleep improvement).

Why Flexeril Was Discontinued?

While Merck, the manufacturer, hasn’t officially stated the reason for discontinuation, it’s widely believed that profitability was the primary factor. The availability of much cheaper generic cyclobenzaprine made it difficult for the brand-name Flexeril to compete. This is a common occurrence when drug patents expire, although the Flexeril situation was somewhat unique.

Merck received FDA approval for Flexeril in 1977, following a patent grant in 1975. Although patents typically last 20 years, generic versions of cyclobenzaprine emerged as early as 1986, leading to legal battles. Merck sued Danbury Pharmacal for patent infringement. Danbury countersued, arguing that Merck’s patent was invalid due to misrepresentations about Flexeril. The court ultimately upheld the patent’s validity but ruled in favor of Danbury on two key points:

Merck failed to disclose the similarity between Flexeril and the existing drug amitriptyline.
Merck inaccurately claimed Flexeril didn’t cause drowsiness.

These legal challenges opened the door for widespread availability of generic cyclobenzaprine.

Is Flexeril (Cyclobenzaprine) Addictive?

When used as prescribed for short periods (typically no more than three weeks), cyclobenzaprine is not considered addictive. However, long-term use or high doses can lead to dependence and misuse. Cyclobenzaprine affects the central nervous system, producing a calming effect that some individuals may find desirable.

Signs of potential dependence or misuse include:

Taking the medication for longer than prescribed
Needing higher doses for the same effect
Using the drug in ways not prescribed (e.g., crushing and snorting)
Preoccupation with the drug
Changes in behavior or appearance

Individuals with mental health conditions may be more susceptible to misusing cyclobenzaprine. Some may use it to self-medicate or to lessen the effects of other substances. Withdrawal symptoms, though usually mild, can occur with chronic, high-dose use.

The Dangers of Combining Flexeril With Other Drugs

Combining cyclobenzaprine with other substances can be extremely dangerous and potentially life-threatening. Mixing it with alcohol or other central nervous system depressants (like barbiturates and benzodiazepines) can lead to excessive drowsiness, slowed breathing, and a dangerously low heart rate.

Combining cyclobenzaprine with certain antidepressants that increase serotonin levels can cause serotonin syndrome, characterized by tremors, sweating, agitation, and potentially high blood pressure. Combining it with MAO inhibitors (a type of antidepressant) can increase the risk of seizures. It can also worsen anticholinergic side effects (dry mouth, dry eyes, constipation) when taken with other anticholinergic medications.

It is crucial to inform your doctor of all medications and supplements you are taking before starting cyclobenzaprine to avoid potentially dangerous drug interactions.

Flexeril Alternatives

Generic cyclobenzaprine is readily available and is essentially the same medication as Flexeril. Other brand-name options include Fexmid and Amrix (an extended-release form). Consult your doctor to discuss the most appropriate option for your needs.

Is Flexeril an Opioid?

No, Flexeril (cyclobenzaprine) is not an opioid. It works differently in the central nervous system. Cyclobenzaprine reduces pain signals by affecting serotonin transmission in the spinal cord, while opioids activate opioid receptors in the brain and body.

Is Flexeril a Controlled Substance?

No, Flexeril is not a controlled substance. While it requires a prescription, it is not regulated by the Drug Enforcement Administration (DEA) as a controlled substance.

Conclusion

While the brand name Flexeril is no longer available, its generic equivalent, cyclobenzaprine, remains a viable option for treating muscle spasms. However, it is essential to use this medication responsibly, under the guidance of a healthcare professional, and be aware of the potential risks associated with its use, especially when combined with other substances. Discuss your treatment options with your doctor to determine the best course of action for your specific situation.

References

Category: Blog