Get help today 888-287-0471 or sign up for 24/7 text support.
American Addiction Centers National Rehabs Directory

Cyclobenzaprine Overdose: The Dangers of Abusing Flexeril

Cyclobenzaprine (Flexeril) Overdose: Signs, Risks & Treatment Options

Cyclobenzaprine is a muscle relaxant that is typically prescribed to relieve pain and stiffness associated with muscle spasms. It belongs to a class of medicines known as skeletal muscle relaxants. Cyclobenzaprine works by blocking the activity of certain nerve cells in the brain. Paired with exercise, rest or physical therapy, this treatment helps relieve muscle stiffness and pain. It is also available under brand names of Amrix and Flexeril.1

Cyclobenzaprine overdose can occur when someone takes more than the recommended amount of the medication, or if they combine cyclobenzaprine with other substances like alcohol or opioids. Symptoms of a cyclobenzaprine overdose may include drowsiness, confusion, agitation, hallucinations, and seizures.1 

If you or someone you know has overdosed on cyclobenzaprine, it’s important to seek medical help immediately. Cyclobenzaprine overdose treatment may vary in intensity based on the severity of the case.2

Can You Overdose on Cyclobenzaprine (Flexeril)?

Cyclobenzaprine is not a controlled substance, but has the potential to be abused due to its effects. Taking too much cyclobenzaprine can lead to overdose and, in rare cases, may have a fatal outcome.2

Cyclobenzaprine is available as a tablet as well as an extended-release capsule administered orally. A cyclobenzaprine tablet is taken orally, typically 2 to 3 times a day, before or after a meal; while the capsule is taken once per day, with or without food.1

The cyclobenzaprine tablet is available in doses of 5mg, 7.5mg, and 10mg. The extended-release capsules can be found in doses of 15mg and 30mg. The maximum recommended daily dose is 30mg.4

The official recommendation is not to exceed these doses or take the treatment for more than three weeks without consulting a doctor. Exceeding the cyclobenzaprine max dose recommended by the doctor may lead to adverse effects.1

What Are The Signs & Symptoms Of Cyclobenzaprine Overdose?

The signs and symptoms of cyclobenzaprine overdose can vary depending on how much is taken. Common symptoms include drowsiness, dizziness, dry mouth, and blurred vision. If someone overdoses on cyclobenzaprine, it is important to seek medical attention immediately.1

Some common symptoms of cyclobenzaprine overdose include:

  • Fast or irregular heartbeats.
  • Drowsiness.
  • Confusion.
  • Agitation.
  • Trouble moving or speaking.
  • Nausea.
  • Vomiting.
  • Dizziness.
  • Hallucinations.
  • Tremors.
  • Losing consciousness.

Among the rare, but potentially fatal manifestations of cyclobenzaprine or flexeril overdose are irregular heartbeats, sudden cardiac arrest, severe hypotension, and NMS (neuroleptic malignant syndrome).4

Several case studies have attributed deaths to a cyclobenzaprine overdose. In two reported cases of cyclobenzaprine overdose, postmortem evaluations revealed elevated levels of the drug.2

What is Cyclobenzaprine Max Dose?

Cyclobenzaprine is a medication that comes in different forms and doses, prescribed depending on various factors. Cyclobenzaprine 5 mg taken three times a day is the most commonly prescribed dosage of the drug. For children, the dosage is lower than for teens or adults. And for older people, the dosage may be a little bit lower than for teens or adults. Comparatively to younger patients, steady-state plasma concentrations of cyclobenzaprine are doubled in elderly patients.4

The maximum dosage for cyclobenzaprine is 30 mg per day. But, if you’re taking other medications, your doctor might start you at a lower dose and then increase it if needed. It takes three to four days for the drug to reach steady-state concentration when taken three times a day. An 18-hour half-life is associated with cyclobenzaprine’s slow elimination from the system.4

In terms of how many mg of cyclobenzaprine it takes to overdose, the data is limited and further studies are needed. However, the analyses of two fatal cyclobenzaprine overdose cases, found that a blood concentration of 0.8 mg/L or more of cyclobenzaprine was associated with the fatal outcome. It is worth noting that in both cases, cyclobenzaprine was used with diazepam and alcohol, respectively.2

What are the Risk Factors of Cyclobenzaprine Overdose?

Although cyclobenzaprine or Flexeril are generally considered safe, there are certain risk factors that may increase the chances of overdosing on the medication. One of the most important risk factors is age. Cyclobenzaprine has been shown to be more dangerous in the elderly. This is likely due to the increased steady-state plasma concentrations of the drug in the elderly.4

Cyclobenzaprine overdose can lead to serious complications, such as serotonin syndrome, neuroleptic malignant syndrome, and other potentially fatal conditions such as cardiac arrest. These complications can be life-threatening, so it is important to get medical help immediately if you or someone you know has overdosed on Flexeril.4,5

Although cyclobenzaprine is not considered addictive, nor is it a controlled substance, there have been reports of cyclobenzaprine abuse. The use of cyclobenzaprine was associated with over 12,000 ER visits in 2010. This marks a 101% increase compared to 2004. The drug is often abused by people who mix it with alcohol or other drugs in order to increase its effects. The drug may cause people to feel relaxed, sedated, and in rare cases euphoric, when misused. Those who abuse cyclobenzaprine are at a naturally higher risk of a Flexeril overdose.6

What are the Factors Impacting Overdose?

There are a number of factors that may impact the severity of a cyclobenzaprine overdose, including the amount of the drug that was taken and whether it was taken with any other medications or substances. The person’s age, weight, and overall health can also play a role in how severe an overdose may be.4

Drug & Alcohol Consumption

An important risk factor in Flexeril overdose is the simultaneous use of alcohol or other drugs while taking cyclobenzaprine, either inadvertently or to amplify its effects. Alcohol and other drugs may affect Flexeril, which can lead to an overdose. Therefore, it is important to avoid drinking alcohol and consult with a doctor about using other drugs while taking cyclobenzaprine.5,6,7

Cyclobenzaprine Interactions

Simultaneous use of cyclobenzaprine with other treatments such as other pro-serotonergic drugs, such as duloxetine and phenelzine, has been recorded to lead to serotonin syndrome. This is a potentially life-threatening condition caused by the heightened levels of serotonin in the body. Symptoms of serotonin syndrome can include agitation, hallucinations, tachycardia and increased blood pressure, sweating, and diarrhea. The symptoms of the condition typically resolve within three days following discontinuation of the pro-serotonergic treatments.5

Cyclobenzaprine may also interact with other medications that affect the nervous system, such as anticonvulsants and antidepressants. Additionally, patients taking treatments for allergies or colds, insomnia, serotonin reuptake inhibitors, or treatments for anxiety, mood swings and depression should discuss the risks of cyclobenzaprine overdose with their physician.1

Personal Factors

There are certain medical conditions that may increase the risk of negative cyclobenzaprine interactions. Conditions such as liver disease, overactive thyroid gland, kidney disease, tachycardia and heart disease can all interact with the drug and increase the chances of cyclobenzaprine overdose side effects. If you have any of these conditions, it is important to talk to your doctor before taking cyclobenzaprine.4

Medicine Usage

Flexeril should only be used for a short-term period of time. Long-term users may develop a tolerance and may need higher doses for the treatment to remain effective. When a person stops using it or reduces the dose, tolerance may lead to physical dependence and withdrawal symptoms, although further studies on long-term use of cyclobenzaprine are required. Therefore, it is the manufacturer’s recommendation to avoid long-term use of the drug.8

How To Prevent Flexeril Overdose?

There is no definitive answer to this question as everyone may have different reactions to Flexeril. If you are concerned about overdosing on Flexeril or cyclobenzaprine, it is best to speak with your doctor or pharmacist. They can give you specific advice on how to avoid an overdose.1

Generally, it is important to take cyclobenzaprine only as directed by your doctor. Do not take more or less cyclobenzaprine than prescribed, and do not take it more often than directed. Additionally, be sure to keep track of how many cyclobenzaprine tablets you have taken. This will help you avoid taking too much Flexeril and increase the risk of overdose. Make sure to take cyclobenzaprine on schedule, preferably at the same time every day to make sure you can follow the schedule easier. If you think you may have overdosed on cyclobenzaprine or Flexeril, seek medical attention immediately.1

If you take cyclobenzaprine, don’t drink alcohol or use drugs that are not prescribed to you. Taking cyclobenzaprine with alcohol or other drugs that are not prescribed to you may increase your risk of overdosing. Purposefully using cyclobenzaprine and alcohol to achieve the effects of sedation or relaxation may lead to an inadvertent cyclobenzaprine overdose.6

Cyclobenzaprine Overdose Treatment

If you believe someone has overdosed on cyclobenzaprine, call 911 or your local poison control center right away. If the person is awake and alert, you may also call the National Poison Control Center at 1-800-222-1222 for advice.1

Some of the symptoms indicating a person needs immediate medical care include:1

  • Collapsing.
  • Seizures.
  • Trouble breathing.
  • Trouble staying awake or waking up.

Treatment for a cyclobenzaprine overdose will vary depending on the severity of the overdose and may include:

  • Gastrointestinal Decontamination: This involves performing a gastric lavage and administering activated charcoal which may help bind the cyclobenzaprine and prevent it from being absorbed into their system.9
  • Cardiovascular interventions: In patients experiencing dysrhythmias caused by cyclobenzaprine overdose, treatment with sodium bicarbonate and hyperventilation may alleviate the symptoms. Patients who do not respond to this treatment may be put on lidocaine, phenytoin or bretylium.9
  • Neurological interventions: Because of the potential for abrupt deterioration in patients with CNS depression, early intubation is recommended. Doctors may use anticonvulsants such as benzodiazepines or other anticonvulsants in the case of seizures.9
  • Supportive care: This includes measures to keep the person comfortable and to treat any symptoms of a cyclobenzaprine overdose. This may include administering IV fluids, oxygen therapy, and monitoring of vital signs and heart functions.9
  • Therapeutic plasma exchange (TPE): This is a medical procedure used to remove harmful substances from the blood. It may be used in cases of severe cyclobenzaprine overdose side effects.10
  • Follow-Up Treatment: In cases when the Flexeril overdose is intentional, follow-up treatment is required to prevent further incidents or suicide attempts. Patients dealing with cyclobenzaprine abuse may need to be referred to an inpatient substance abuse program to deal with their addiction. Other treatment options for those with a less severe case of abuse may need a medical detox to safely get the drug out of their system or may be referred to outpatient treatment, where they can continue living at home while receiving treatment for addiction.9,11

These treatments should be administered by a licensed physician only. Do not attempt to administer any of these treatments yourself unless instructed to by a physician or a medical expert. If you or someone you love experiences a cyclobenzaprine overdose, it is important to seek medical help immediately. An overdose of this drug can be dangerous and even life-threatening.

What to Do In Case of a Cyclobenzaprine Overdose?

If you or a loved one overdose on cyclobenzaprine, you should call 911 immediately. Other helpful resources and hotlines for Cyclobenzaprine overdose prevention and treatment include the SAMHSA helpline at 1-800-662-HELP (4357) or the American Addiction Centers available at this website. If you are thinking about harming yourself, please call the National Suicide Prevention Lifeline at 1-800-273-8255. You can also call the National Poison Control Center at 1-800-222-1222 for further instructions on helping a loved one who is responsive and conscious through a cyclobenzaprine overdose.12

If you are looking for information regarding addiction treatment for Cyclobenzaprine abuse, it is important to know that many treatment centers accept insurance to help cover the costs of addiction treatment. The admissions navigators at AAC can help you find the right detox and inpatient treatment program to start your recovery from prescription drug abuse. They can also check whether your insurance will cover treatment, help you locate the nearest treatment center and provide information on payment options if you do not have insurance.

Was this page helpful?
Thank you for your feedback.

American Addiction Centers (AAC) is committed to delivering original, truthful, accurate, unbiased, and medically current information. We strive to create content that is clear, concise, and easy to understand.

Read our full editorial policy

While we are unable to respond to your feedback directly, we'll use this information to improve our online help.