Table of ContentsView AllTable of ContentsHow It WorksDosingHow Long It’s EffectiveSide EffectsSafely Taking CyclobenzaprineHow Effective Is It?Managing Muscle InjuriesFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
How It Works
Dosing
How Long It’s Effective
Side Effects
Safely Taking Cyclobenzaprine
How Effective Is It?
Managing Muscle Injuries
Frequently Asked Questions
Cyclobenzaprineis a generic prescription medication classified as askeletal muscle relaxantormuscle relaxant. It is used along with other measures like rest andphysical therapyto relax the muscles and relieve pain and discomfort due to sprains, strains, and other muscle injuries.
If your healthcare provider prescribes cyclobenzaprine, you may be feeling a lot of discomfort and wonder how long the effects of this will medication last. The short answer is that a dose of cyclobenzaprine can last up to six or 24 hours, depending on the formulation, although it may take one or two days initially to start working.
This in-depth article will cover the effects of cyclobenzaprine and provide other important information about this medicine.
grandriver / Getty Images
What Is Cyclobenzaprine and How Does It Work?
Cyclobenzaprine is a skeletal muscle relaxant. It works in the brain (not directly on muscles) to help relieve muscle spasms.
This medication should only be used for a short time, generally up to three weeks. Though cyclobenzaprine can help symptoms associated with musculoskeletal conditions, it is not effective in treating spasms associated with conditions of the nervous system, likecerebral palsy.
Dosing Cyclobenzaprine
Cyclobenzaprine dosing is as follows:
For How Long Is Cyclobenzaprine Effective?
Immediate-release cyclobenzaprine starts working quickly (within about one hour) and reaches its maximum effect within about four hours. However, noticing the full benefit of this medicine may take one or two days.
A dose of immediate-release cyclobenzaprine may be effective in four to six hours.Therefore, it can be prescribed to take three times daily (or about once every eight hours).
A dose of extended-release cyclobenzaprine reaches its maximum effect within about seven to eight hours. Because this formulation is designed to release over time, one dose can last up to 24 hours.This formulation is taken once daily or about once every 24 hours.
Cyclobenzaprine Leaving the Body
Thehalf-life of a drugis the time it takes for one-half of a dose of the drug to be eliminated from the body. It takes about five half-lives for a drug to be mostly eliminated from the body if you stop taking it.
The average half-life of immediate-release cyclobenzaprine is 18 hours but can range from 8 to 37 hours.
This means that, on average, when you stop taking cyclobenzaprine, it will be mostly out of the body within 90 (18 x 5) hours but could range from 40 hours (about 1.5 days; 8 hours x 5 half-lives) to 185 hours (almost 8 days; 37 hours x 5 half-lives).
If you take Amrix (extended-release cyclobenzaprine), however, the average half-life is 32 hours (a little more than one day), and it would take about 160 hours (almost 7 days) for it to completely leave the body.
Common side effects of cyclobenzaprine include:
Call your healthcare provider right away if you experience serious side effects. Call 911 if your symptoms feel life-threatening or if you think you have a medical emergency. Serious side effects can include the following:
Before taking cyclobenzaprine, tell your healthcare provider about all of your medical conditions and all the medications you take, including:
Avoid alcohol while taking cyclobenzaprine. Do not drive until you know how cyclobenzaprine affects you.
Some examples of interacting drugs include:
You should not take cyclobenzaprine if:
Also, in some instances, cyclobenzaprine should be taken with caution, such as in individuals:
If you take extended-release cyclobenzaprine, swallow the capsule whole. Do not chew or crush it. You can also sprinkle the contents of the capsule on 1 tablespoon of applesauce and swallow right away without chewing the mixture.
If you think you took too much cyclobenzaprine, call Poison Control at 1-800-222-1222 right away or call 911 and go to the emergency room. Overdose symptoms may include:
One review of many studies found cyclobenzaprine to be more effective than placebo (inactive medicine) in managingback painbut noted that the effect was modest and associated with greater side effects. The researchers found that cyclobenzaprine was most effective in the first four days of treatment.
However, whether any muscle relaxant is better than only using nonsteroidal anti-inflammatory drugs (NSAIDs) for treating acute lower back pain has come into question.
A review published in 2022 found no significant improvement in people treated in the emergency room for low back pain with an NSAID and cyclobenzaprine or any of six other skeletal muscle relaxants compared to treatment with an NSAID and a placebo.
Experts note that cyclobenzaprine is the most studied muscle relaxant, and studies have found it effective for musculoskeletal conditions.
Additionally, the side effect of sedation may help people who have trouble sleeping but could be a concern for older adults who may have an increased risk of injury due to sedation.
The findings among various clinical studies show that cyclobenzaprine is most effective in the first few days of taking it.
Cyclobenzaprine and other muscle relaxants lack evidence of effectiveness for longer-term use and are generally recommended for a maximum of two to three weeks.
Because everyone is different, it’s best to consult your healthcare provider for more information about cyclobenzaprine. Your provider can weigh the risks and benefits, taking your specific medical history into consideration and determining whether it is appropriate for you.
Pain and discomfort from strains or sprains are generally treated with over-the-counter or prescription oral or topically appliednonsteroidal anti-inflammatory drugs(NSAIDs) and/ormuscle relaxants.Note thatTylenol(acetaminophen) is not an NSAID and does not help with symptoms of inflammation.
You can help prevent muscle injuries with these practices:
If you have an injury, make sure you are completely healed before resuming activity.
Baclofen vs. Cyclobenzaprine: Similarities and Differences
Summary
Cyclobenzaprine is a muscle relaxant used for short-term (up to three weeks) treatment of sprains, strains, and other muscle injuries. This medication should be taken along with other measures, like rest and physical therapy.
Immediate-release cyclobenzaprine starts to work within an hour and lasts for four to six hours. Because of this, it can be taken up to three times daily. Extended-release cyclobenzaprine works over time, with one dose lasting up to 24 hours. Because of this, it is taken only once per day.
You can consult your healthcare provider for more information about muscle injuries and which treatment is appropriate for you. It carries a risk of sedation, so exercise caution when taking this medication.
Frequently Asked QuestionsStore cyclobenzaprine at room temperature away from direct light, heat, and moisture. Do not store it in the bathroom. As with all medications, keep out of reach and sight of children and pets. Keep the bottle tightly closed when not in use.Learn MorePillboxes and Medication SafetyThese drugs do not interact and can be taken together. However, although Tylenol can help with pain, it does not help with swelling and inflammation. If you have inflammation, an NSAID may be more helpful than Tylenol. Check with your healthcare provider or pharmacist to see whether you can take an NSAID with any medical conditions you have and medications you take.Learn MoreHow Does Tylenol (Acetaminophen) Work?Experts recommend using ice for acute injuries like sprains and strains. Especially during the first few days, ice can help with swelling and bruising. Heat can actually make an acute injury worse. Heat is best for chronic pain (pain lasting longer than four weeks or an older injury) or after swelling has decreased.Learn MoreHow to Avoid Frostbite From an Ice Pack
Store cyclobenzaprine at room temperature away from direct light, heat, and moisture. Do not store it in the bathroom. As with all medications, keep out of reach and sight of children and pets. Keep the bottle tightly closed when not in use.Learn MorePillboxes and Medication Safety
Store cyclobenzaprine at room temperature away from direct light, heat, and moisture. Do not store it in the bathroom. As with all medications, keep out of reach and sight of children and pets. Keep the bottle tightly closed when not in use.
Learn MorePillboxes and Medication Safety
These drugs do not interact and can be taken together. However, although Tylenol can help with pain, it does not help with swelling and inflammation. If you have inflammation, an NSAID may be more helpful than Tylenol. Check with your healthcare provider or pharmacist to see whether you can take an NSAID with any medical conditions you have and medications you take.Learn MoreHow Does Tylenol (Acetaminophen) Work?
These drugs do not interact and can be taken together. However, although Tylenol can help with pain, it does not help with swelling and inflammation. If you have inflammation, an NSAID may be more helpful than Tylenol. Check with your healthcare provider or pharmacist to see whether you can take an NSAID with any medical conditions you have and medications you take.
Learn MoreHow Does Tylenol (Acetaminophen) Work?
Experts recommend using ice for acute injuries like sprains and strains. Especially during the first few days, ice can help with swelling and bruising. Heat can actually make an acute injury worse. Heat is best for chronic pain (pain lasting longer than four weeks or an older injury) or after swelling has decreased.Learn MoreHow to Avoid Frostbite From an Ice Pack
Experts recommend using ice for acute injuries like sprains and strains. Especially during the first few days, ice can help with swelling and bruising. Heat can actually make an acute injury worse. Heat is best for chronic pain (pain lasting longer than four weeks or an older injury) or after swelling has decreased.
Learn MoreHow to Avoid Frostbite From an Ice Pack
20 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.MedlinePlus.Cyclobenzaprine.Prescribers’ Digital Reference (PDR).Cyclobenzaprine hydrochloride.DailyMed.Cyclobenzaprine hydrochloride tablet, film coated.Forte ML, Butler M, Andrade KE, et al.Treatments for fibromyalgia in adult subgroups. Rockville (MD): Agency for Healthcare Research and Quality (US); 2015 Jan. (Comparative Effectiveness Reviews, No. 148.) Appendix A, Medications Used Off Label for Fibromyalgia Syndrome in the United States.Kia S, Choy E.Update on treatment guideline in fibromyalgia syndrome with focus on pharmacology.Biomedicines. 2017;5(2):20. doi:10.3390/biomedicines5020020National Library of Medicine.Long-term use of cyclobenzaprine for pain: a review of the clinical effectiveness.Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; February 23, 2015.de Lima Souza Brioschi TM, Schramm SG, Kano EK, et al.Pharmacokinetics and bioequivalence evaluation of cyclobenzaprine tablets.Biomed Res Int. 2013;2013:281392. doi:10.1155/2013/281392Borenstein DG, Korn S.Efficacy of a low-dose regimen of cyclobenzaprine hydrochloride in acute skeletal muscle spasm: results of two placebo-controlled trials.Clin Ther. 2003;25(4):1056-1073. doi:10.1016/s0149-2918(03)80067-xDarwish M, Hellriegel ET.Steady-state pharmacokinetics of once-daily cyclobenzaprine extended release: a randomized, double-blind, 2-period crossover study in healthy volunteers.Clin Ther. 2011;33(6):746-753. doi:10.1016/j.clinthera.2011.05.045Hallare J, Gerriets V.Half life. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.DailyMed.Amrix.Soprano SE, Hennessy S, Bilker WB, et al.Assessment of physician prescribing of muscle relaxants in the United States, 2005-2016.JAMA Netw Open. 2020;3(6):e207664. doi:10.1001/jamanetworkopen.2020.7664Chaffee D.Cyclobenzaprine in the treatment of low back pain.afp. 2016;93(3).Abril L, Zamora C, Cordero M, et al.The relative efficacy of seven skeletal muscle relaxants. an analysis of data from randomized studies.J Emerg Med. 2022;62(4):455-461. doi:10.1016/j.jemermed.2021.09.025Frydrych V, Oderda G.Skeletal muscle drug class review. University of Utah College of Pharmacy. 2016.See S, Ginzburg R.Choosing a skeletal muscle relaxant.Am Fam Physician. 2008;78(3):365-370.University of Rochester Medical Center.Sprains, strains, breaks: What’s the difference?Hauk L.Low back pain: American College of Physicians Practice Guideline on Noninvasive Treatments.Am Fam Physician. 2017;96(6):407-408.Johns Hopkins Medicine.Preventing sports injuries.Hospital for Special Surgery.Ice or heat: What’s best for your pain?
20 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.MedlinePlus.Cyclobenzaprine.Prescribers’ Digital Reference (PDR).Cyclobenzaprine hydrochloride.DailyMed.Cyclobenzaprine hydrochloride tablet, film coated.Forte ML, Butler M, Andrade KE, et al.Treatments for fibromyalgia in adult subgroups. Rockville (MD): Agency for Healthcare Research and Quality (US); 2015 Jan. (Comparative Effectiveness Reviews, No. 148.) Appendix A, Medications Used Off Label for Fibromyalgia Syndrome in the United States.Kia S, Choy E.Update on treatment guideline in fibromyalgia syndrome with focus on pharmacology.Biomedicines. 2017;5(2):20. doi:10.3390/biomedicines5020020National Library of Medicine.Long-term use of cyclobenzaprine for pain: a review of the clinical effectiveness.Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; February 23, 2015.de Lima Souza Brioschi TM, Schramm SG, Kano EK, et al.Pharmacokinetics and bioequivalence evaluation of cyclobenzaprine tablets.Biomed Res Int. 2013;2013:281392. doi:10.1155/2013/281392Borenstein DG, Korn S.Efficacy of a low-dose regimen of cyclobenzaprine hydrochloride in acute skeletal muscle spasm: results of two placebo-controlled trials.Clin Ther. 2003;25(4):1056-1073. doi:10.1016/s0149-2918(03)80067-xDarwish M, Hellriegel ET.Steady-state pharmacokinetics of once-daily cyclobenzaprine extended release: a randomized, double-blind, 2-period crossover study in healthy volunteers.Clin Ther. 2011;33(6):746-753. doi:10.1016/j.clinthera.2011.05.045Hallare J, Gerriets V.Half life. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.DailyMed.Amrix.Soprano SE, Hennessy S, Bilker WB, et al.Assessment of physician prescribing of muscle relaxants in the United States, 2005-2016.JAMA Netw Open. 2020;3(6):e207664. doi:10.1001/jamanetworkopen.2020.7664Chaffee D.Cyclobenzaprine in the treatment of low back pain.afp. 2016;93(3).Abril L, Zamora C, Cordero M, et al.The relative efficacy of seven skeletal muscle relaxants. an analysis of data from randomized studies.J Emerg Med. 2022;62(4):455-461. doi:10.1016/j.jemermed.2021.09.025Frydrych V, Oderda G.Skeletal muscle drug class review. University of Utah College of Pharmacy. 2016.See S, Ginzburg R.Choosing a skeletal muscle relaxant.Am Fam Physician. 2008;78(3):365-370.University of Rochester Medical Center.Sprains, strains, breaks: What’s the difference?Hauk L.Low back pain: American College of Physicians Practice Guideline on Noninvasive Treatments.Am Fam Physician. 2017;96(6):407-408.Johns Hopkins Medicine.Preventing sports injuries.Hospital for Special Surgery.Ice or heat: What’s best for your pain?
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.
MedlinePlus.Cyclobenzaprine.Prescribers’ Digital Reference (PDR).Cyclobenzaprine hydrochloride.DailyMed.Cyclobenzaprine hydrochloride tablet, film coated.Forte ML, Butler M, Andrade KE, et al.Treatments for fibromyalgia in adult subgroups. Rockville (MD): Agency for Healthcare Research and Quality (US); 2015 Jan. (Comparative Effectiveness Reviews, No. 148.) Appendix A, Medications Used Off Label for Fibromyalgia Syndrome in the United States.Kia S, Choy E.Update on treatment guideline in fibromyalgia syndrome with focus on pharmacology.Biomedicines. 2017;5(2):20. doi:10.3390/biomedicines5020020National Library of Medicine.Long-term use of cyclobenzaprine for pain: a review of the clinical effectiveness.Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; February 23, 2015.de Lima Souza Brioschi TM, Schramm SG, Kano EK, et al.Pharmacokinetics and bioequivalence evaluation of cyclobenzaprine tablets.Biomed Res Int. 2013;2013:281392. doi:10.1155/2013/281392Borenstein DG, Korn S.Efficacy of a low-dose regimen of cyclobenzaprine hydrochloride in acute skeletal muscle spasm: results of two placebo-controlled trials.Clin Ther. 2003;25(4):1056-1073. doi:10.1016/s0149-2918(03)80067-xDarwish M, Hellriegel ET.Steady-state pharmacokinetics of once-daily cyclobenzaprine extended release: a randomized, double-blind, 2-period crossover study in healthy volunteers.Clin Ther. 2011;33(6):746-753. doi:10.1016/j.clinthera.2011.05.045Hallare J, Gerriets V.Half life. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.DailyMed.Amrix.Soprano SE, Hennessy S, Bilker WB, et al.Assessment of physician prescribing of muscle relaxants in the United States, 2005-2016.JAMA Netw Open. 2020;3(6):e207664. doi:10.1001/jamanetworkopen.2020.7664Chaffee D.Cyclobenzaprine in the treatment of low back pain.afp. 2016;93(3).Abril L, Zamora C, Cordero M, et al.The relative efficacy of seven skeletal muscle relaxants. an analysis of data from randomized studies.J Emerg Med. 2022;62(4):455-461. doi:10.1016/j.jemermed.2021.09.025Frydrych V, Oderda G.Skeletal muscle drug class review. University of Utah College of Pharmacy. 2016.See S, Ginzburg R.Choosing a skeletal muscle relaxant.Am Fam Physician. 2008;78(3):365-370.University of Rochester Medical Center.Sprains, strains, breaks: What’s the difference?Hauk L.Low back pain: American College of Physicians Practice Guideline on Noninvasive Treatments.Am Fam Physician. 2017;96(6):407-408.Johns Hopkins Medicine.Preventing sports injuries.Hospital for Special Surgery.Ice or heat: What’s best for your pain?
MedlinePlus.Cyclobenzaprine.
Prescribers’ Digital Reference (PDR).Cyclobenzaprine hydrochloride.
DailyMed.Cyclobenzaprine hydrochloride tablet, film coated.
Forte ML, Butler M, Andrade KE, et al.Treatments for fibromyalgia in adult subgroups. Rockville (MD): Agency for Healthcare Research and Quality (US); 2015 Jan. (Comparative Effectiveness Reviews, No. 148.) Appendix A, Medications Used Off Label for Fibromyalgia Syndrome in the United States.
Kia S, Choy E.Update on treatment guideline in fibromyalgia syndrome with focus on pharmacology.Biomedicines. 2017;5(2):20. doi:10.3390/biomedicines5020020
National Library of Medicine.Long-term use of cyclobenzaprine for pain: a review of the clinical effectiveness.Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; February 23, 2015.
de Lima Souza Brioschi TM, Schramm SG, Kano EK, et al.Pharmacokinetics and bioequivalence evaluation of cyclobenzaprine tablets.Biomed Res Int. 2013;2013:281392. doi:10.1155/2013/281392
Borenstein DG, Korn S.Efficacy of a low-dose regimen of cyclobenzaprine hydrochloride in acute skeletal muscle spasm: results of two placebo-controlled trials.Clin Ther. 2003;25(4):1056-1073. doi:10.1016/s0149-2918(03)80067-x
Darwish M, Hellriegel ET.Steady-state pharmacokinetics of once-daily cyclobenzaprine extended release: a randomized, double-blind, 2-period crossover study in healthy volunteers.Clin Ther. 2011;33(6):746-753. doi:10.1016/j.clinthera.2011.05.045
Hallare J, Gerriets V.Half life. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.
DailyMed.Amrix.
Soprano SE, Hennessy S, Bilker WB, et al.Assessment of physician prescribing of muscle relaxants in the United States, 2005-2016.JAMA Netw Open. 2020;3(6):e207664. doi:10.1001/jamanetworkopen.2020.7664
Chaffee D.Cyclobenzaprine in the treatment of low back pain.afp. 2016;93(3).
Abril L, Zamora C, Cordero M, et al.The relative efficacy of seven skeletal muscle relaxants. an analysis of data from randomized studies.J Emerg Med. 2022;62(4):455-461. doi:10.1016/j.jemermed.2021.09.025
Frydrych V, Oderda G.Skeletal muscle drug class review. University of Utah College of Pharmacy. 2016.
See S, Ginzburg R.Choosing a skeletal muscle relaxant.Am Fam Physician. 2008;78(3):365-370.
University of Rochester Medical Center.Sprains, strains, breaks: What’s the difference?
Hauk L.Low back pain: American College of Physicians Practice Guideline on Noninvasive Treatments.Am Fam Physician. 2017;96(6):407-408.
Johns Hopkins Medicine.Preventing sports injuries.
Hospital for Special Surgery.Ice or heat: What’s best for your pain?
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