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Flexeril (Cyclobenzaprine) Addiction

Posted on February 6, 2013 in Prescription Drug Addiction

After Whitney Houston drowned in her hotel bathtub February 11, 2012, the Los Angeles coroner identified five drugs in her body — cocaine, marijuana, cyclobenzaprine, Benadryl, and Xanax. Just nine months before her death, the pop singer had begun treatment for an addiction to cocaine, a powerful drug that stimulates the central nervous system.

Like many coke addicts, she probably found it hard to relax and “come down” without sedatives. Xanax is an anti-anxiety drug, Benadryl is an antihistamine that can cause drowsiness, and cyclobenzaprine is a muscle relaxant. The three of them together along with marijuana would cause severe mental impairment and slow down the central nervous to a dangerous point. A normal but sleepy adult would have been startled back to life after falling underwater in a bathtub. But Whitney Houston, under the influence of these drugs, might have been simply too sedated to realize she was drowning and to pull herself up for air.

Cyclobenzaprine, sold under the brand name Flexeril, is a muscle relaxant commonly prescribed for injuries and sprains. In 2012, doctors wrote over 26 million prescriptions for it, making it widely available. The United States Drug Enforcement Agency lists it as “a drug of concern” and one that is frequently diverted from legitimate medical purposes to recreational use. Those who abuse cyclobenzaprine use it to enhance the effect of mind-altering drugs or combine with alcohol and other depressants to induce deep states of relaxation.

Although Flexeril is not classified as addictive, the drug can cause an unpleasant withdrawal syndrome.

Abuse of Flexeril is increasing, most likely because the Department of Justice classified the other most popular muscle relaxant, Soma, as a Schedule IV Controlled Substance in 2012.

What Is Flexeril?

Flexeril is the trademarked name of a drug called cyclobenzaprine, which relaxes muscles and reduces pain, although no one is exactly sure just how it accomplishes those things.

Cyclobenzaprine is chemically related to a family of drugs called tricyclic antidepressants, invented in the 1950s and one of the first remedies for depression. Animal studies indicate that the effects of certain tricyclic antidepressants are very similar to those of Flexeril. Like the tricyclics, Flexeril prevents a neurotransmitter called norepinephrine from returning to its cells of origin, thus increasing the amount of norepinephrine in the body. It seems to act in the central nervous system at the brainstem and not in the spinal cord, which is where most central nervous system depressants act. Cyclobenzaprine probably decreases pain by blocking nerve impulses to the brain.

Cyclobenzaprine comes as a white crystalline tricycle amine salt soluble in water and alcohol. Its chemical name is 3-(5H-dibenzo[a,d]cyclohepten-5-ylidene)- N,N-dimethyl-1-propanamine.

What Are the Medical Uses of Flexeril?

McNeil Consumer and Pharmaceuticals manufactures Flexeril, the trademarked brand of cyclobenzaprine. It is available as capsules, tablets, and in solution form, and the extended release version is called Amrix.

Flexeril is prescribed for skeletal muscle conditions, including muscle strains and sprains, and severe back pain. The drug is to be used along with rest, exercise, and sometimes a program of physical therapy. Flexeril and other cyclobenzaprine products are prescribed off-label for fibromyalgia.

Flexeril is only supposed to be prescribed for two weeks because research indicates it is most effective within the first two days and stops working within fourteen days.

The usual dosage for people over 15 years of age is 10mg taken three times a day, which can be increased to 60mg a day if needed. The extended release version is usually taken once a day at a 15mg level, which can be increased to 30mg as needed.

It usually takes between 30 minutes to an hour for Flexeril to take effect.

Who Should Not Take Flexeril?

Flexeril should not be taken by people with heart conditions, such as congenital heart failure, heart blockages, and heart rhythm disorders. It is not prescribed to people with enlarged prostate glands, glaucoma, overactive thyroids, or liver diseases.

Flexeril is not usually prescribed to children under 15 years of age. It is rarely used among patients over 65 years old, because it increases drowsiness and their risk for falls. Elderly bodies also take longer to metabolize and eliminate drugs, allowing them sometimes to build up to unhealthy levels.

Cyclobenzaprine is a Category B drug for pregnant women, which means the studies of its effect on fetuses are inadequate.

What Are the Side Effects of Flexeril?

Studies of people taking Flexeril found that 38% experienced drowsiness, 24% dry mouth, and 10% had dizziness.

Some patients have complained about other side effects. Since these have not been adequately tested in double-blind studies with placebos, no one knows for sure if the side effects are the result of the medication. These include blurred vision, fatigue, diarrhea, constipation, muscle weakness, ringing in the ears, skin rashes, unusual thoughts, yellow eyes or skin, feeling as if you have the flu, headache, problems with speech, sleep, and urination, depression, and clumsiness.

Some people have had to stop taking Flexeril because they said it produced fast heartbeat, sudden numbness, chest pain, sudden headache, fainting, nausea, hallucinations, seizures, low fever, and abnormal bruising or bleeding.

What Are the Dangers of Taking Flexeril?

The U.S. federal government does not classify Flexeril as an addictive substance even though people have become psychologically dependent on similar drugs that produce feelings of relaxation. Cyclobenzaprine can cause an unpleasant withdrawal syndrome, which is a criterion for any addictive substance.

If you abuse Flexeril or other cyclobenzaprine products in extreme amounts or take it with certain other drugs, you can develop “anticholinergic toxidome,” which is caused by inhibiting certain neurotransmitters in the central nervous system. Symptoms can be confusion, hallucinations, visual disturbances, inability to think clearly, unusual fears or thoughts, and so forth. The syndrome can lead to seizures, coma, and death, usually by heart attack.

In very rare cases some people have allergic reactions to cyclobenzaprine that can be life-threatening. They will find it hard to breathe, and their faces, tongues, lips, and throats will swell. They may develop rashes, hives, wheezing, fast heart rates, and other serious symptoms within a matter of seconds. Allergic shock or anaphylaxis can be treated in emergency medical facilities.

What Drugs Interact With Flexeril?

Combining Flexeril or other cyclobenzaprine products with Monoamine Oxidase Inhibitors such as isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, selegiline, or tranylcypromine can result in death. Doctors recommend that you stop taking MAO Inhibitors for at least 14 days before you start a Flexeril regime.

When you combine Flexeril with drugs that cause drowsiness or depress the central nervous system, you run the risk of slowing down your breathing to the point that it will stop and you will die. Flexeril increases the sedative effects of antidepressants, anti-histamines, illegal narcotics like heroin, legal narcotic painkillers like OxyContin, alcohol, barbiturates, sleeping pills, tranquilizers, and other depressants. Do not combine Flexeril with cold and allergy medicines or antihistamines, such as cetirizine, diphenhydramine, anti-anxiety drugs such as alprazolam, diazepam, and zolpidem, other muscle relaxants, or anti-depressants like escitapram (Lexapro) or floxetine (Prozac).

If you combine cyclobenzaprine with marijuana, you will experience severe mental impairment. If you combine it with alcohol, you will depress your brain function.

Flexeril should not be taken with Donnatal, Congentin, Dramamine, Pamine, Transderm, Robinul, Ismelin, Cantil, or Ultram. Because Flexeril is chemically similar to tricyclic antidepressants like amitriptyline and imipramine, you should not combine these drugs. Do not take Flexeril with medications for seizures, urinary problems or irritable bowel syndrome.

Does Flexeril Show Up In Drug Urine Tests?

Routine urine drug tests performed at workplaces and schools will detect the presence of cyclobenzaprine. The drug has a half-life of 18 hours, which means it will probably stay active in your body for 90 hours. Therefore, it will show up on drug tests for 3.75 days after you have taken it, but this time period may vary by individual. If a person has a bad liver or a kidney problem, the drug may stay in their bodies longer.

What Is A Flexeril Overdose?

Flexeril overdoses occur when a person takes the drug in amounts not medically recommended. Symptoms can be convulsions, severe drowsiness, flushed hot skin, fast or irregular heartbeat, hallucinations, an increase or decrease in body temperature, severe nervousness, vomiting, muscle stiffness, and trouble breathing. The syndrome is rarely fatal, especially if the person gets medical treatment.

A two-year study of 3974 poisoning cases of cyclobenzaprine and a very similar drug, amitripline, found that those taking amitripline alone or in combination with cyclobenzaprine were more likely to have seizures and to enter comas. The 209 people who overdosed on cyclobenzaprine by itself all survived, although two had seizures and three developed hypotension.

Over 12,000 people a year seek emergency treatment for drug overdoses involving cyclobenzaprine.

What Is Flexeril Discontinuation Syndrome?

When you stop taking Flexeril, you may experience certain unpleasant symptoms called “a discontinuation or withdrawal syndrome.” Flexeril is only supposed to be used for two weeks, but when people use it for years or abuse it in large amounts, they are more likely to develop the syndrome. Flexeril withdrawal syndrome is similar to what happens when you stop taking tricyclic antidepressants.

Symptoms are similar to flu: nausea, vomiting, sweating, difficulty sleeping, and muscle aches. Doctors sometimes help their patients avoid the syndrome by slowly tapering off the amounts of cyclobenzaprine their patients are taking.

What Is Flexeril Abuse?

Researchers from the U. S. Drug Enforcement Agency have found that the majority of people who abuse Flexeril are using other illegal and/or prescription drugs along with it. They often take cyclobenzaprine products to enhance the effects of alcohol, barbiturates, benzodiazepines, and narcotics (including narcotic painkillers).Or they may take cyclobenzaprine by itself as a sleeping pill or to achieve deep states of relaxation, which one person described as “having legs of jelly.” If taken in high amounts, the drug can create the feeling that the user is floating out of his or her body. Some people have experienced euphoria and hallucinations taking Flexeril, although the drug is not considered as “good a high” as Soma.

The street name for Flexeril is mellow yellow or cyclone.

In research that tracked emergency room visits involving prescription drug abuse, five percent or 23,500 of the over 500,000 incidents reported in 2005 were about carisoprodol or cyclobenzaprine, but this number is probably increasing. The American Association of Poison Control Centers reported 12,411 cases of poisoning involving carisoprodol in 2010 compared to 6,183 such incidences in 2004.

Flexeril abuse is increasing partly because muscle relaxants containing carisoprodol were reclassified it as Schedule IV Controlled Substances in 2012. This classification requires doctors and pharmacies to keep more detailed records of the dispensing of the drug, and means that people who are caught illegally possessing it can incur heavy fines and/or prison sentences. Products containing cyclobenzaprine are still not classified as controlled substances, and therefore doctors are more likely to prescribe them, and these drugs are more likely to be available illegally on the Internet.

The National Survey on Drug Abuse and Health indicated that over 12% of Americans ages 18 to 24 years old have experimented with prescription drugs for nonmedical reasons, and over two percent have chemical dependencies on such drugs. The vast majority of these young people –94%– did not buy their drugs from street dealers. Sixty-seven percent obtained them from medicine cabinets owned by family and friends or through illegal Internet pharmacies. This pattern of purchase is no doubt similar for Flexeril abuse.

How Can I Tell If I Am Abusing Flexeril?

If you are using any cyclobenzaprine product under a doctor’s supervision, if you have been using it as prescribed and for fourteen days or less, you would not be considered a drug abuser. On the other hand, if you can answer yes to any of the questions below, it may be time to consult your family physician, an addiction specialist or a local mental health center about your drug problem.

  • Have you been using Flexeril for more than two weeks?
  • Are you taking Flexeril or other cyclobenzaprine products in amounts greater than 60mg a day?
  • Are you taking Flexeril without a doctor’s prescription?
  • Do you take Flexeril and other drugs for non-medical reasons — for example, to relax or to get high?
  • Do you experience withdrawal symptoms when you stop using drugs?
  • Do you use Flexeril or other cyclobenzaprine products in combination with alcohol, marijuana, or “downers”?
  • Do you use Flexeril to come down from cocaine or other stimulants, or to get to sleep?
  • Do you find it impossible to go more than a day or two without taking drugs for non-medical reasons?
  • Do members of your family or your friends criticize you for your drug problems?
  • Have you tried on your own to quit using drugs but failed?
  • Do you feel guilty or ashamed about your use of drugs?
  • Do you feel that your use of drugs is beyond your control?

What Treatments Are Available For Drug Dependency?

Drug dependency is no longer considered just a behavioral problem, but rather a disease of the brain. Certain drugs interfere with certain brain chemicals that regulate feelings of pleasure. If these drugs are abused over a long period of time and in great amounts, a person can develop cravings for drugs, tolerance to their effects, and withdrawal syndromes when he or she tries to quit. Tolerance means that you have to take a drug in increasingly greater amounts in order to achieve the same effects you did in the past. Once a physical and psychological dependency on drugs takes over, you are no longer in control of the situation, and using drugs is no longer a choice for you.

In order to overcome an addiction to drugs, you need help on several levels: physical, spiritual, mental, and emotional. Most people have to make radical lifestyle changes, giving up friends who use drugs, even if those people are family members or spouses. They have to learn to handle drug cravings that will continue to occur long after they stopped using drugs. They have to find new pleasure in life from other activities, such as sports and hobbies, and socialize with people who do not abuse drugs. Sometimes they have to change careers and family situations that are self-destructive and contributing to their drug abuse.

Most people who enter treatment centers for drug or alcohol addictions have what doctors call comorbidities, medical issues that contribute to but do not cause their addictions. The most common comorbidities are depression, unresolved childhood traumas, bipolar or personality disorders, posttraumatic stress syndrome, and attention deficit disorders. These have to be treated in separate medical protocols with separate kinds of psychotherapy and medications. The staff of a good rehabilitation center can usually treat any comorbidity along with addiction.

The first step to becoming free of drugs is to enter a residential drug treatment center, where you start your recovery with a complete medical and psychiatric examination. A team of staff members specializing in different disciplines evaluates your individual case and comes up with an individualized protocol for you.

The next step is chemical detoxification or the actual physical withdrawal from drugs and alcohol. Medical professionals supervise your detoxification and sometimes prescribe drugs to ease your discomfort.

Once you have achieved detoxification, you reside at the treatment center and work through your program with others on similar journeys of recovery. Your program might include intense individual psychotherapy, family and group counseling, classes in drug addiction, and therapies involving art, drama and music. You might learn relaxation techniques like yoga and meditation to help you handle the inevitable relapses and cravings now considered part of recovery. Once you return home, you usually remain in an aftercare program of continued individual and family therapy and self-help support meetings.


“Whitney Houston Enters Drug, Alcohol Rehab,” CBS News, May 9, 2011, see

Lovett, Ian. “Whitney Houston Drowned,” The New York Times, March 22, 2012. See The Physicians’ Desk Reference, 66th Edition (2011) for the side effects of Benadryl, cyclobenzaprine, and Xanax.

“Cyclobenzaprine,”  A Pamphlet from the U.S. Drug Enforcement Agency, see

“Cyclobenzaprine,”  Drug of Concern, The U.S. Drug Enforcement Agency, see

Griffin, Winter (MD). The Complete Guide to Prescription and Nonprescription Drugs, 2011. New York: Perigee Books, 2011, page 288.

Data from the Drug Abuse Warning Network, see “Placement of Carisoprodol Into Schedule IV,” The Department of Justice, Federal Register, Volume76 Issue 238, December 12, 2011, see

Cyclobenzaprine (Oral Route),” The Staff at Mayo Clinic, see

“Cyclobenzaprine,”  A Pamphlet from the U.S. Drug Enforcement Agency, see

“Flexeril,”, Official Information from the U.S. Food and Drug Administration, see

“Cyclobenzaprine,”  A Pamphlet from the U.S. Drug Enforcement Agency, see

“Flexeril,”, Official Information from the U.S. Food and Drug Administration, see

Chou R, Peterson K, Helfand M (2004). “Comparative efficacy and safety of skeletal muscle relaxants for spasticity and musculoskeletal conditions: a systematic review”. Journal of Pain Symptom Management 28 (2): 140–175

“Cyclobenzaprine (Oral Route),” The Staff at Mayo Clinic, see

Griffin, Winter (MD). The Complete Guide to Prescription and Nonprescription Drugs, 2011. New York: Perigee Books, 2011, page 288.

“Flexeril,”, Official Information from the U.S. Food and Drug Administration, see

“Cyclobenzaprine (Oral Route),” The Staff at Mayo Clinic, see

Browning R, Jackson JL, O’Malley PG (2001). “Cyclobenzaprine and back pain: a meta-analysis”. Archives of Internal Medicine 16(13): 1613–1620

“Cyclobenzaprine (Oral Route),” The Staff at Mayo Clinic, see

1“Flexeril,”, Official Information from the U.S. Food and Drug Administration, see

“Anticholinergic toxicity,” the University of Maryland Poison Control Center, see

“Flexeril,”, Official Information from the U.S. Food and Drug Administration, see

“Cyclobenzaprine (Oral Route),” The Staff at Mayo Clinic, see

Griffin, Winter (MD). The Complete Guide to Prescription and Nonprescription Drugs, 2011. New York: Perigee Books, 2011, page 288.


“Cyclobenzaprine,” The WebMD, see

“Cyclobenzaprine (Oral Route),” The Staff at Mayo Clinic, see

Bebarta, V. et al. Incidence of tricyclic antidepressant-like complications after cyclobenzaprine overdose. American Journal of Emergency Medicine (2011) 29, 645–649.

“National All Schedules Prescription Electronic Reporting Act of 2005: A Review of Implementation of Existing State Controlled Substance Monitoring Programs,” a 110-page pamphlet from the U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services, see

“Cyclobenzaprine,”  A Pamphlet from the U.S. Drug Enforcement Agency, see

See websites posted and maintained by drug users.

“National All Schedules Prescription Electronic Reporting Act of 2005: A Review of Implementation of Existing State Controlled Substance Monitoring Programs,” a 110-page pamphlet from the U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services, see

“Cyclobenzaprine,”  A Pamphlet from the U.S. Drug Enforcement Agency, see

“National All Schedules Prescription Electronic Reporting Act of 2005: A Review of Implementation of Existing State Controlled Substance Monitoring Programs,” a 110-page pamphlet from the U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services, see


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