No, cyclobenzaprine is not a controlled substance. However, it is a muscle relaxant available by prescription only, and there is anecdotal evidence that it is increasingly being abused to achieve psychoactive effects or increase the effects of other illicit drugs.
People with a history of substance use disorder or drug abuse should ask their doctor about alternatives to cyclobenzaprine. Others, such as those with hypothyroidism, heart rhythm disorder, or congestive heart failure, should also avoid this prescription medication.
What Is Cyclobenzaprine?
Cyclobenzaprine is a prescription muscle relaxant used to treat skeletal issues, including muscle spasms and pain caused by injuries such as strains and sprains. It is often prescribed on a short-term basis alongside physical therapy and rest.
Also known as the brand names Amrix, Fexmid, and Flexeril, cyclobenzaprine is not a controlled substance and is not currently considered a significant risk of abuse or addiction, but some case reports and studies suggest a potential for misuse, particularly in combination with other substances. [1] Like other prescription drugs, it should be taken under the guidance of a medical professional and is not available over the counter.
Side Effects of Cyclobenzaprine
This prescription muscle relaxant has been associated with some common side effects, including: [2]
- Drowsiness
- Dry mouth
- Dizziness
- Constipation
- Fatigue
- Nausea
Mild side effects of cyclobenzaprine may not require medical attention. Individuals should contact their healthcare provider if these symptoms become severe or persist for more than a few days.
Before Taking Cyclobenzaprine
Even though cyclobenzaprine isn’t a controlled substance, there are still precautions one should take before beginning a regimen of cyclobenzaprine. A doctor can help weigh the risks and benefits of cyclobenzaprine for muscle pain or spasms.
Possible Cyclobenzaprine Drug Interactions
There is a long list of medications that may interact with cyclobenzaprine. Before prescribing this drug, doctors should know about any other substances a patient is taking, including over-the-counter and recreational drugs. Here are some medications to avoid while taking cyclobenzaprine: [3]
- Phenelzine
- Selgiline
- Thioridazine
- Potassium chloride
- Cisapride
- Rasagiline
- Ozanimod
- Bepridil
- Dronedarone
- Linezolid
Prior Medical Conditions
Before taking cyclobenzaprine, individuals should tell their doctor about any medical conditions they have. Some of these medical conditions may not react well to cyclobenzaprine, including: [4]
- Liver disease
- Heart disease
- Thyroid issues
- Pregnancy (or breastfeeding)
- Glaucoma
- Bladder problems
- Depression
- Migraines
- Enlarged prostate
Cyclobenzaprine Dosage Information
Muscle relaxants such as cyclobenzaprine are typically prescribed for the short-term relief of muscle pain or injury. Doctors typically do not prescribe it for more than three weeks. [5]Here are some other things to know before taking cyclobenzaprine:
- Any other medications currently being used should be reported to the doctor to avoid any dangerous drug interactions.
- Cyclobenzaprine should be taken with a glass of water, with or without food.
- Cyclobenzaprine should be taken exactly as prescribed, taking care not to increase the dosage without specific instructions from a health care provider.
- Cyclobenzaprine is typically taken three times a day; the extended-release formulation should be taken only once a day.
- Extended-release cyclobenzaprine should be swallowed whole, not crushed, split in half, or chewed.
- A missed dose should be skipped if it’s close to the time for the next dose. It’s not advised to take a double dose of this drug.
- If symptoms don’t improve or get worse after three weeks, a healthcare provider should be notified.
- Cyclobenzaprine should not be taken alongside alcohol or other drugs, especially opioid drugs.
Risk of Flexeril Abuse and Addiction
Under the U.S. Controlled Substances Act, Flexeril, or cyclobenzaprine, is not a high-risk substance when it comes to abuse and addiction, but some case reports and studies suggest a potential for misuse, particularly in combination with other substances. [6]This could change in the future due to the increasing anecdotal evidence that this muscle relaxant is being misused for recreational purposes. The risk of addiction is still considered low, but this risk increases when the drug is used in higher doses or mixed with other drugs, including alcohol.
Signs of Cyclobenzaprine Overdose
Having an addiction to a substance such as cyclobenzaprine can increase the risk of a life-threatening overdose. Since this drug is a central nervous system depressant, there is the risk of it slowing or stopping breathing in higher doses or when mixed with other CNS depressants such as alcohol or opioids. Signs and symptoms of a cyclobenzaprine overdose include: [7]
- Tremor or shakiness
- Trouble moving
- Trouble speaking
- Extreme drowsiness
- Confusion
- Dizziness
- Hallucinations (visual or auditory)
- Nausea
- Vomiting
- Agitation
- Rapid heartbeat
- Irregular heartbeat
In the case of an overdose, call 911. This is a medical emergency. Call the poison control center.
Consider Substance Use and Addiction Treatment
Compassionate substance use and addiction recovery services are available, so individuals and families don’t have to face these frightening issues alone. Cyclobenzaprine is not considered addictive in the same way as opioids or benzodiazepines, but misuse and psychological dependence can occur, particularly in individuals with a history of substance use disorders.
