Cyclobenzaprine (Flexeril) Uses, Side Effects, & Risks
Cyclobenzaprine is a drug prescribed to treat pain and discomfort. This page will go over its side effects, drug interactions, and treatment for misuse.
What is Cyclobenzaprine (Flexeril)?
How cyclobenzaprine (Flexeril) works is not well understood, but it helps alleviate stiffness, pain, and discomfort due to sprains, strains, or injuries to muscles. It is also sometimes prescribed off-label to treat fibromyalgia pain.1
Cyclobenzaprine may be referred to by the former brand name Flexeril, though generic and other brands exist.
Cyclobenzaprine usually begins working about one hour after it is ingested, relaxing muscles and relieving muscle spasms. Formulations include immediate-release and extended-release.2 If you are prescribed cyclobenzaprine, follow your healthcare provider’s directions for how to take it.
How Long Is Cyclobenzaprine Effective?
Cyclobenzaprine works for 4-6 hours.3 However, the half-life of immediate-release cyclobenzaprine is 18 hours on average, with a range of 8-37 hours. The extended-release form typically has a half-life of 32-33 hours.2
Common Cyclobenzaprine Side Effects
Common Flexeril side effects include:3
- Drowsiness
- Blurred vision
- Dry mouth
- Lightheadedness
- Dizziness
It is also possible for serious cyclobenzaprine side effects to occur, like seizures, heart arrhythmias, heart attack, or stroke. These are more likely to occur when a person has too much cyclobenzaprine in their system, for instance, if their prescription dose is too high or if they are misusing the drug.
Because there is not enough evidence that cyclobenzaprine is effective for long-term use, and because the muscle spasms it is indicated for are generally of short duration, it is typically prescribed for no longer than two to three weeks.4,5 If cyclobenzaprine is being misused, however, the person may continue to take the medication for much longer and may increase their dose too high, which could lead to dangerous side effects and overdose.
Cyclobenzaprine Interactions with Other Substances
Cyclobenzaprine can increase the effects of CNS depressants, such as alcohol, opioids, allergy medications, and sleeping pills. It can also interact with other medications.1 If a person is prescribed cyclobenzaprine, they should make sure their health care provider knows all medications they are taking (including over-the-counter medications), as well as if they drink alcohol or use other drugs. This enables the provider to evaluate for any potential interactions and helps them keep the patient safe. Even if it feels like the effects of cyclobenzaprine have worn off, the drug may not be completely eliminated from the body yet and could cause serious interactions with other substances.
Cyclobenzaprine (Flexeril) Detox & Withdrawal
Upon abrupt cessation of chronic cyclobenzaprine use, some people have reported some cyclobenzaprine withdrawal. Cyclobenzaprine withdrawal symptoms may include:
- Nausea.
- Headache.
- A general feeling of discomfort.
Treatment for Cyclobenzaprine (Flexeril) Misuse
While the addictiveness of cyclobenzaprine is being debated, anyone exhibiting problematic patterns of substance use can benefit from addiction treatment. This is especially true if someone has been engaging in polydrug use with cyclobenzaprine and other substances.
Laguna Treatment Center—our rehab facility in Orange County, CA—utilizes effective, evidence-based approaches through a variety of levels of addiction treatment that can help you or your loved one get sober and remain in recovery.
These levels of care include:
Call to speak to a compassionate admissions navigator who can help you through the admissions process or answer questions about insurance coverage and other ways to pay for rehab.