Table of ContentsView AllTable of ContentsSkeletal Muscle RelaxantsWhat Is Cyclobenzaprine?Cyclobenzaprine and SleepinessDosingSide EffectsAlternative Treatment OptionsPros and ConsFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Skeletal Muscle Relaxants
What Is Cyclobenzaprine?
Cyclobenzaprine and Sleepiness
Dosing
Side Effects
Alternative Treatment Options
Pros and Cons
Frequently Asked Questions
The Food and Drug Administration (FDA) has approvedcyclobenzaprineformuscle-based injuriesin addition to rest andphysical therapy.
Cyclobenzaprineis an orally administered drug that relieves muscle spasms and reduces related tenderness, making it easier to return to normal activities.
However,muscle relaxants, including cyclobenzaprine, can causedrowsiness. You may start feeling drowsy about 30 minutes after taking a dose; sleepiness may persist for six to eight hours.
However, you likely won’t need to take cyclobenzaprine for long—it’s typically only prescribed short term, as needed, for less than three weeks.
Read on for more information on the consumption of cyclobenzaprine.
Wladimir Bulgar / Getty Images
Understanding Skeletal Muscle Relaxants
Muscle spasmsoccur when contractions tighten your muscles involuntarily.
Spasms are uncontrollable, unpredictable, and can be disruptive and painful. Muscle spasms occur when muscles tighten involuntarily.
They may feel like pain knots in your muscles. Muscle spasms can develop due to injuries, overuse, poor posture, stress, etc. Furthermore, they can involve all or part of a muscle or several different muscles.
Muscle spasms are common but present differently in different people.
Some muscle spasms may be mild and last briefly, while others may be persistent or occur repeatedly.
Drug Options
Other prescription skeletal muscle relaxants (muscle relaxers) that can be alternatives to cyclobenzaprine include:
Cramps vs. Spasms
For context, muscle spasms are not the same as muscle cramps.
Cyclobenzaprine was initially approved under Flexeril, but the brand-name version has since been discontinued.
Usage
Cyclobenzaprine should only be used for up to three weeks.
Long-term use of cyclobenzaprine is not usually necessary because the drug is intended to relieve acute (short-term) muscle spasms rather than spasms that persist due to chronic conditions.
Cyclobenzaprine is approved for use in adults and children ages 15 years and older.
How It Works
Cyclobenzaprine works in the central nervous system (CNS), which includes the brain and spinal cord. It acts as a depressant, slowing certain activities in the CNS.
Cyclobenzaprine reduces overactive signals in the CNS that lead to excessive muscle contractions and resulting spasms.
Cyclobenzaprine is considered a CNS depressant but is not a controlled substance and is non-addicting.
Off-Label Uses
It is possible that cyclobenzaprine can be prescribed for other conditions off-label.
“Off label” refers to a drug being prescribed for a different reason than the indications listed in the drug’s FDA-approved label.
Cyclobenzaprine may be used off-label to manage:
In addition, some evidence suggests that cyclobenzaprine may have a role in improving sleep quality in people withposttraumatic stress disorder (PTSD).
Amrix, a name-brand, ER capsule version of cyclobenzaprine, is typically dosed once daily.
How Long Does Cyclobenzaprine Make You Sleepy?
Cyclobenzaprine causes drowsiness due to its effects on thecentral nervous system (CNS), which consists of the brain and spinal cord.
The drug acts on receptors responsible for regulating muscle movements and relaxing tense and tightened muscles.
Due to its ability to depress or slow CNS activity, cyclobenzaprine may cause you to feel sleepy, tired, or lacking energy.
However, the severity of drowsiness a person may experience with cyclobenzaprine can range from not drowsy to lethargic (extreme sluggishness); it varies with the individual.
Limiting Drowsiness
In clinical studies, approximately 39% of individuals taking cyclobenzaprine experienced drowsiness. So, not everyone feels sleepy after taking it.
To limit drowsiness, you can take cyclobenzaprine close to bedtime instead of when you need to be alert.
If you constantly feel lethargic or excessively sleepy while taking cyclobenzaprine, speak with a healthcare provider. They may recommend a lower dose or a different treatment option for you.
Duration of Effect
After taking a dose of cyclobenzaprine, you may start feeling tired or more relaxed within 30 minutes. This feeling could last for around eight hours after taking each dose.
The half-life of cyclobenzaprine is 18 hours. For context, half-life measurement is the time required for the body to clear half a drug dose.
It usually takes five half-lives for the body to clear a drug to the point that it is no longer detectable in the blood.
So, after you stop taking it, cyclobenzaprine should be out of your system within about four days.
How Long Do the Effects of Cyclobenzaprine Last?
Dosing Guidelines
The typical cyclobenzaprine dosage for people 15 years and older is 5 milligrams (mg) taken up to three times daily. Doses are usually taken eight hours apart.
Sometimes, the dose may be increased to 10 mg every eight hours, as needed.
Healthcare providers may recommend a lower dose for older adults or individuals with liver problems.
Stiff Muscles
ER capsule form:
Tablet form:
Safe Consumption Guidelines
Since the drug commonly causes drowsiness, avoid taking it before you need to drive or perform other activities requiring alertness.
Avoid alcohol while taking cyclobenzaprine, which can increase the drowsiness side effect and impair cognitive function.
Side Effects & Precautions
Like all drugs, cyclobenzaprine may cause some unwanted side effects.
As such, be sure to monitor yourself or a loved one for the emergence of side effects.
If side effects from cyclobenzaprine worsen or fail to dissipate, contact your healthcare provider immediately.
Common Side Effects
Common side effects of cyclobenzaprine include:
Severe Side Effects
Severe side effects of cyclobenzaprine may include:
Mild musculoskeletal injuries and spasms can sometimes go away without medication.
Some examples of other ways to relieve muscle spasms and musculoskeletal pain without taking a muscle relaxer include:
Remember that cyclobenzaprine is meant to be used in addition to physical therapy and rest; taking the medication isn’t a replacement for either of these essential strategies for relieving muscle spasms.
Is cyclobenzaprine right for you?
Below is a summary of the pros and cons of taking cyclobenzaprine. You can consult a healthcare provider for personalized advice.
Tell them about your medical history and current medications, including prescription, over-the-counter (OTC), and supplements, to determine if taking cyclobenzaprine is safe.
Summary
Muscle relaxers, such as cyclobenzaprine, are an effective treatment for muscle spasms, rest, and physical therapy. It is an effective medication to treat uncontrolled and sometimes painful muscle spasms.
Because of its depressant effects on the CNS, cyclobenzaprine can cause drowsiness as a side effect.
This side effect can start within 30 minutes and last about eight hours after a dose.
The individual response can vary; lethargy and tiredness do not constantly occur in everyone who takes cyclobenzaprine.
Frequently Asked QuestionsCyclobenzaprine should bestoredin a cool, dry place away from moisture, kept at room temperature (68-77 F), and out of reach of pets and children.Probably not, since the medication may cause drowsiness and reduced alertness.To be safe, don’t plan on getting behind the wheel or operating heavy machinery after taking cyclobenzaprine.No, cyclobenzaprine is not designed to help with muscle spasms due tospinal cord injuryor brain damage.Cyclobenzaprine works to help reduce muscle tension and spasms, but not in the context of these conditions, partly because cyclobenzaprine does not work directly on muscles.
Cyclobenzaprine should bestoredin a cool, dry place away from moisture, kept at room temperature (68-77 F), and out of reach of pets and children.
Probably not, since the medication may cause drowsiness and reduced alertness.To be safe, don’t plan on getting behind the wheel or operating heavy machinery after taking cyclobenzaprine.
Probably not, since the medication may cause drowsiness and reduced alertness.
To be safe, don’t plan on getting behind the wheel or operating heavy machinery after taking cyclobenzaprine.
No, cyclobenzaprine is not designed to help with muscle spasms due tospinal cord injuryor brain damage.Cyclobenzaprine works to help reduce muscle tension and spasms, but not in the context of these conditions, partly because cyclobenzaprine does not work directly on muscles.
No, cyclobenzaprine is not designed to help with muscle spasms due tospinal cord injuryor brain damage.
Cyclobenzaprine works to help reduce muscle tension and spasms, but not in the context of these conditions, partly because cyclobenzaprine does not work directly on muscles.
12 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Library of Medicine: DailyMed.Label: cyclobenzaprine-cyclobenzaprine hydrochloride tablet, film coated.National Library of Medicine: MedlinePlus.Cyclobenzaprine.American Association of Neurological Surgeons.Spasticity – causes, symptoms and treatments.National Library of Medicine: MedlinePlus.Muscle cramps.National Library of Medicine: LiverTox.Muscle relaxants.Stern, L. Bernick, C.Clinical Methods: The History, Physical, and Laboratory Examinations.3rd edition.Chapter 53: Muscle cramps.Singh K, Senatorov IS, Cheshmehkani A, Karmokar PF, Moniri NH.The skeletal muscle relaxer cyclobenzaprine is a potent non-competitive antagonist of histamine H1 receptors.J Pharmacol Exp Ther. 2022;380(3):202-209. doi:10.1124/jpet.121.000998Liu Y, Qian C, Yang M.Treatment patterns associated with ACR-recommended medications in the management of fibromyalgia in the United States.J Manag Care Spec Pharm.2016;22(3):263-271. doi:10.18553/jmcp.2016.22.3.263Sullivan GM, Gendreau RM, Gendreau J, et al.Randomized clinical trial of bedtime sublingual cyclobenzaprine (TNX-102 SL) in military-related PTSD and the role of sleep quality in treatment response.Psychiatry Res.2021;301:113974. doi:10.1016/j.psychres.2021.113974National Library of Medicine: DailyMed.Label: Amirix- cyclobenzaprine hydrochloride capsule, extended release.Smith DA, Beaumont K, Maurer TS, Di L.Relevance of half-life in drug design.J Med Chem. 2018;61(10):4273-4282. doi:10.1021/acs.jmedchem.7b00969Centers for Disease Control and Prevention.A national strategy for occupational musculoskeletal injuries: implementation issues and research needs.
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Library of Medicine: DailyMed.Label: cyclobenzaprine-cyclobenzaprine hydrochloride tablet, film coated.National Library of Medicine: MedlinePlus.Cyclobenzaprine.American Association of Neurological Surgeons.Spasticity – causes, symptoms and treatments.National Library of Medicine: MedlinePlus.Muscle cramps.National Library of Medicine: LiverTox.Muscle relaxants.Stern, L. Bernick, C.Clinical Methods: The History, Physical, and Laboratory Examinations.3rd edition.Chapter 53: Muscle cramps.Singh K, Senatorov IS, Cheshmehkani A, Karmokar PF, Moniri NH.The skeletal muscle relaxer cyclobenzaprine is a potent non-competitive antagonist of histamine H1 receptors.J Pharmacol Exp Ther. 2022;380(3):202-209. doi:10.1124/jpet.121.000998Liu Y, Qian C, Yang M.Treatment patterns associated with ACR-recommended medications in the management of fibromyalgia in the United States.J Manag Care Spec Pharm.2016;22(3):263-271. doi:10.18553/jmcp.2016.22.3.263Sullivan GM, Gendreau RM, Gendreau J, et al.Randomized clinical trial of bedtime sublingual cyclobenzaprine (TNX-102 SL) in military-related PTSD and the role of sleep quality in treatment response.Psychiatry Res.2021;301:113974. doi:10.1016/j.psychres.2021.113974National Library of Medicine: DailyMed.Label: Amirix- cyclobenzaprine hydrochloride capsule, extended release.Smith DA, Beaumont K, Maurer TS, Di L.Relevance of half-life in drug design.J Med Chem. 2018;61(10):4273-4282. doi:10.1021/acs.jmedchem.7b00969Centers for Disease Control and Prevention.A national strategy for occupational musculoskeletal injuries: implementation issues and research needs.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Library of Medicine: DailyMed.Label: cyclobenzaprine-cyclobenzaprine hydrochloride tablet, film coated.National Library of Medicine: MedlinePlus.Cyclobenzaprine.American Association of Neurological Surgeons.Spasticity – causes, symptoms and treatments.National Library of Medicine: MedlinePlus.Muscle cramps.National Library of Medicine: LiverTox.Muscle relaxants.Stern, L. Bernick, C.Clinical Methods: The History, Physical, and Laboratory Examinations.3rd edition.Chapter 53: Muscle cramps.Singh K, Senatorov IS, Cheshmehkani A, Karmokar PF, Moniri NH.The skeletal muscle relaxer cyclobenzaprine is a potent non-competitive antagonist of histamine H1 receptors.J Pharmacol Exp Ther. 2022;380(3):202-209. doi:10.1124/jpet.121.000998Liu Y, Qian C, Yang M.Treatment patterns associated with ACR-recommended medications in the management of fibromyalgia in the United States.J Manag Care Spec Pharm.2016;22(3):263-271. doi:10.18553/jmcp.2016.22.3.263Sullivan GM, Gendreau RM, Gendreau J, et al.Randomized clinical trial of bedtime sublingual cyclobenzaprine (TNX-102 SL) in military-related PTSD and the role of sleep quality in treatment response.Psychiatry Res.2021;301:113974. doi:10.1016/j.psychres.2021.113974National Library of Medicine: DailyMed.Label: Amirix- cyclobenzaprine hydrochloride capsule, extended release.Smith DA, Beaumont K, Maurer TS, Di L.Relevance of half-life in drug design.J Med Chem. 2018;61(10):4273-4282. doi:10.1021/acs.jmedchem.7b00969Centers for Disease Control and Prevention.A national strategy for occupational musculoskeletal injuries: implementation issues and research needs.
National Library of Medicine: DailyMed.Label: cyclobenzaprine-cyclobenzaprine hydrochloride tablet, film coated.
National Library of Medicine: MedlinePlus.Cyclobenzaprine.
American Association of Neurological Surgeons.Spasticity – causes, symptoms and treatments.
National Library of Medicine: MedlinePlus.Muscle cramps.
National Library of Medicine: LiverTox.Muscle relaxants.
Stern, L. Bernick, C.Clinical Methods: The History, Physical, and Laboratory Examinations.3rd edition.Chapter 53: Muscle cramps.
Singh K, Senatorov IS, Cheshmehkani A, Karmokar PF, Moniri NH.The skeletal muscle relaxer cyclobenzaprine is a potent non-competitive antagonist of histamine H1 receptors.J Pharmacol Exp Ther. 2022;380(3):202-209. doi:10.1124/jpet.121.000998
Liu Y, Qian C, Yang M.Treatment patterns associated with ACR-recommended medications in the management of fibromyalgia in the United States.J Manag Care Spec Pharm.2016;22(3):263-271. doi:10.18553/jmcp.2016.22.3.263
Sullivan GM, Gendreau RM, Gendreau J, et al.Randomized clinical trial of bedtime sublingual cyclobenzaprine (TNX-102 SL) in military-related PTSD and the role of sleep quality in treatment response.Psychiatry Res.2021;301:113974. doi:10.1016/j.psychres.2021.113974
National Library of Medicine: DailyMed.Label: Amirix- cyclobenzaprine hydrochloride capsule, extended release.
Smith DA, Beaumont K, Maurer TS, Di L.Relevance of half-life in drug design.J Med Chem. 2018;61(10):4273-4282. doi:10.1021/acs.jmedchem.7b00969
Centers for Disease Control and Prevention.A national strategy for occupational musculoskeletal injuries: implementation issues and research needs.
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