How Long Does Flexeril Stay in Your System?
Learn about Flexeril, how long it stays in the body, and treatment methods for Flexeril addiction.
A Discussion on Flexeril
Flexeril is one of the many brand names for cyclobenzaprine and is used as a short-term treatment for muscle spasms. Flexeril is a muscle relaxant that works by blocking nerve impulses or pain sensations sent to your brain.1
For this article, we’ll be referring to cyclobenzaprine as Flexeril, one of the most common brand names containing the active ingredient.

THINKING ABOUT TREATMENT?
Call Us Anytime: 1-866-754-0180
Common Flexeril Online Searches
Since Flexeril is quite often misused and potentially very dangerous, it is regularly checked for in drug tests. As a result, there are many online searches related to the following topics:
- How long does Flexeril stay in your system?
- What is the Flexeril half-life?
- What does the Cyclobenzaprine drug test entail?
- How does the Flexeril narcotic drug test work?
- Does Flexeril make you drowsy?
- Why does Flexeril make me sleepy?
A word of caution must be given to anyone abusing this drug and attempting to cheat on cyclobenzaprine drug tests by asking questions like how long does Flexeril stay in your system?
Flexeril abuse and cheating on drug tests are hazardous and potentially fatal actions. Therefore, speaking to a medical professional for help can go a long way and potentially result in treatment and recovery. In addition, always stick to the prescribed Flexeril dosage and never misuse the drug.
What Is Flexeril?
Flexeril is a central nervous system (CNS) muscle relaxant intended for short-term use to treat pain, tenderness, and limitation of motion caused by muscle spasms.
Flexeril may enhance the effects of other CNS depressants, including alcohol, barbiturates, benzodiazepines, and narcotics, and anecdotal reports indicate it is used non-medically to induce euphoria and relaxation.2
Flexeril tablets contain the following inactive ingredients:
- Hydroxypropyl cellulose
- Hydroxypropyl methylcellulose
- Iron oxide
- Lactose
- Magnesium stearate
- Starch
- Titanium dioxide
What Is Flexeril Used to Treat?
Flexeril oral tablets help relax muscles and relieve pain, stiffness, or discomfort caused by strains or injuries to muscles. Flexeril is often prescribed for back pain. Flexeril dosage should always be discussed with a medical professional.
It’s used along with rest and physical therapy. This medication should only be used for two to three weeks at a time. In addition, Flexeril may be used as part of combination therapy, meaning it can be taken with other medications.3
How Does Flexeril Work?
Flexeril is a centrally acting skeletal muscle relaxant structurally related to tricyclic antidepressants. It relieves skeletal muscle spasms of local origin without interfering with muscle function. Research indicates that it primarily operates within the central nervous system in the brain stem.
Flexeril does not work directly on skeletal muscle or the neuromuscular junction, although an overlapping action on the spinal cord may contribute to its overall skeletal muscle relaxant activity.
Evidence implies that the resultant impact of a Flexeril dose is a decline of tonic somatic motor activity, affecting both gamma(γ) and alpha(α) motor systems. Additionally, recent research suggests that Flexeril is a (5-HT2) receptor antagonist, meaning this additional action is responsible for its antispasmodic effect.
Flexeril is an antispasmodic drug that effectively treats muscle spasms, reduces local pain and tenderness, and increases range of motion in acute, painful musculoskeletal conditions.4
What Are the Side Effects of Flexeril?
- Indigestion
- Drowsiness
- Dizziness
- Low energy
- Nausea
- Pain spreading to the jaw or shoulder
- Chest pain or pressure
- Blurred vision
- Taste impairment
- Headache

What Risks Are Associated with Flexeril?
Flexeril is a powerful and potentially addictive drug that is often misused; therefore, dosages should be strictly adhered to. If someone is not adhering to the Flexeril dosage or using Flexeril without a prescription, this is considered misuse—putting them at risk of health problems and potential addiction.
Trazodone and Flexeril
Using trazodone together with cyclobenzaprine can increase the risk of a severe condition called serotonin syndrome, which may cause the following symptoms:
- Confusion
- Hallucinations
- Tremors
- Stomach cramps
- Nausea
- Vomiting
- Diarrhea
Flexeril Contraindications
- Overactive thyroid gland
- Wide-angle glaucoma
- Glaucoma, increased pressure in the eye
- Heart attack within the last thirty days
- Heart block, slowed heart rhythm disorder
- Sinus tachycardia, a type of fast heart rate
- Abnormal heart rhythm
- Chronic heart failure
- Severe liver disease
- An inability to completely empty the bladder
- Thyroid disorder
- Recent heart attack
How Long Does Flexeril Stay in Your System?
The question, how long does Flexeril stay in your system? is commonly asked when trying to mislead a cyclobenzaprine drug test, which is often associated with misuse and potential addiction. Please note that this information is purely informative and is in no way intended to assist in the misleading of a Flexeril narcotic drug test.
As an estimate, after taking a dose of Flexeril, it should be out of the system within 5.5 days to 16.5 days. Thus, the Flexeril half-life is between one and three days. This is the time it takes for the body to reduce the plasma drug levels by half. Flexeril is therefore considered to be eliminated slowly from the body.
It usually takes around 5.5 x half-life for a drug to be eliminated from the system. For Flexeril, one would calculate (5.5 x 1) 5.5 days to (5.5 x 3) 16.5 days.7
Further Factors
Other factors to consider when calculating the duration Flexeril stays in the body include:
- How much and how often the drug was taken.
- Metabolic rate—a slower metabolism will increase the time a drug remains in the system.
- Age and health—older age and poor health will generally increase the time the drug stays in the system.
- Body mass—generally, the bigger a person is, the longer a drug will remain in their system.
Drug Detection Tests
Flexeril can be tested in the following methods:
- Urine—Detectable up to thirteen days since last taken
- Hair—Detectable up to three days since last taken
- Blood—Detectable for up to ten days since last taken
- Saliva—Detectable for up to two days since last taken
Treatment for Flexeril Abuse
Flexeril is a highly addictive drug that can cause physical, emotional, and psychological dependence. Treatment for Flexeril addiction includes some of the following elements.:
Cognitive-Behavioral Therapy
Cognitive-behavioral therapy (CBT) is a type of psychotherapy in which negative patterns of thought about the self and the world are challenged to alter unwanted behavior patterns and treat drug addiction issues.
Group Therapy
Group therapy is a form of psychotherapy that involves sessions guided by a therapist and attended by several clients who confront their drug dependency problems.
Medication-Assisted Treatment
Medication-assisted treatment (MAT) uses medications in combination with counseling and behavioral therapies to provide a “whole-patient” approach to treating substance use disorders.
To learn more about Flexeril addiction and how to overcome it, reach out to our staff at Concise Recovery today. We will help you find the road to healing so that Flexeril or any other substance will never retain control of your life again.
Resources
- https://www.drugs.com/flexeril.html
- https://www.deadiversion.usdoj.gov/drug_chem_info/cyclobenzaprine.pdf
- https://www.medicalnewstoday.com/articles/cyclobenzaprine-oral-tablet#about
- https://www.ncbi.nlm.nih.gov/books/NBK513362/#:~:text=Go%20to%3A-,Mechanism%20of%20Action,cyclobenzaprine%20reduced%20skeletal%20muscle%20hyperactivity.
- https://www.webmd.com/drugs/2/drug-11372/flexeril-oral/details/list-sideeffects
- https://www.webmd.com/drugs/2/drug-11372/flexeril-oral/details/list-contraindications
- https://www.drugs.com/medical-answers/how-long-does-flexeril-stay-in-your-system-374063/#:~:text=Official%20Answer&text=As%20an%20estimate%20then%20%2C%20after,plasma%20drug%20levels%20by%20half.