Muscle relaxers are prescription medications that help regulate muscle contraction (tightening) to reduce pain and discomfort caused by muscle spasms and muscle spasticity (stiffness).

Short-term use of muscle relaxers relieves pain caused by tense or spasming muscles and improves daily functioning. 1 Barreto TW, Lin KW. Noninvasive Treatments for Low Back Pain. American Family Physician. 2017;96(5):324-327. Accessed August 14, 2023. https://www.aafp.org/pubs/afp/issues/2017/0901/p324.html

Muscle relaxers are the third most prescribed medication for low back pain. 2 Cashin AG, Folly T, Bagg MK, et al. Efficacy, acceptability, and safety of muscle relaxants for adults with non-specific low back pain: systematic review and meta-analysis. BMJ. 2021;374:n1446. Published 2021 Jul 7. doi:10.1136/bmj.n1446

Watch this Lower Back Strain Video in our Video Center.

Lower back strain is acute pain caused by damage to the muscles and ligaments of the back. It is often referred to as a pulled muscle. The back is supported by a large, complex group of muscles that hold up the spine, including the extensor, flexor, and oblique muscles. The soft tissues surrounding the spine enable bending forward, lifting, arching, and twisting movements.

Lumbar muscle strain occurs when a back muscle is over-stretched or torn, which damages the muscle fibers. When one of the ligaments in the back tears, it is referred to as a sprain.

Movements that put stress on the back can result in pulled muscles. For example, lifting a heavy object, twisting while lifting, falling, or some sports could cause lumbar muscle strain.

Symptoms of lumbar muscle strain include sudden onset of pain, localized pain that does not radiate into the leg, and tenderness in the lower back.

Muscle strain can be accompanied by muscle spasms, as the body tries to stabilize the injury.

Acute pain from a lower back strain can resolve in a short amount of time, but low levels of pain or flare-ups can continue for weeks or months after the initial injury. After two weeks, back muscles can atrophy from lack of use and cause more pain.

There are many treatment options for lower back muscle strain, including exercise, which will prevent atrophy.

In This Article:

When Muscle Relaxers are Prescribed

Muscle relaxants alleviate pain by reducing muscle spasms and tensions.

Muscle relaxers are prescribed when there is severe pain, discomfort, and/or functional disability due to muscle spasms or stiffness. 1 Barreto TW, Lin KW. Noninvasive Treatments for Low Back Pain. American Family Physician. 2017;96(5):324-327. Accessed August 14, 2023. https://www.aafp.org/pubs/afp/issues/2017/0901/p324.html  The decision to prescribe a muscle relaxer is based on the following factors: 

  • When over-the-counter (OTC) and non-drug therapies (eg, physical therapy, stretching, or heat therapy) are ineffective 1 Barreto TW, Lin KW. Noninvasive Treatments for Low Back Pain. American Family Physician. 2017;96(5):324-327. Accessed August 14, 2023. https://www.aafp.org/pubs/afp/issues/2017/0901/p324.html
  • To prevent muscle spasms/stiffness and potential injury following spine surgery or during a physical therapy session 1 Barreto TW, Lin KW. Noninvasive Treatments for Low Back Pain. American Family Physician. 2017;96(5):324-327. Accessed August 14, 2023. https://www.aafp.org/pubs/afp/issues/2017/0901/p324.html
  • In addition to OTC pain medication, rest, physical therapy, and other non-drug therapies to relieve discomfort and improve function 3 Conermann T, Christian D. Carisoprodol. [Updated 2022 Nov 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK553077/

The duration of treatment is generally short (2-3 weeks). 4 Li Y, Delcher C, Reisfield GM, Wei YJ, Brown JD, Winterstein AG. Utilization Patterns of Skeletal Muscle Relaxants Among Commercially Insured Adults in the United States from 2006 to 2018. Pain Med. 2021;22(10):2153-2161. doi:10.1093/pm/pnab088

Factors that Affect the Type of Muscle Relaxer Prescribed

Choosing a muscle relaxer depends on the cause of the pain (muscle spasms or stiffness, or both). 

Potential side effects and medication interactions, concomitant medical conditions, and personal preferences are also considered.

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Types of Prescription Muscle Relaxers

Muscle relaxers are categorized based on their ability to treat stiffness, spasms, or both.

  • Antispastic drugs. These medications reduce tightness in the muscle through various mechanisms in the brain and directly within the muscle tissue. 5 Rivelis Y, Zafar N, Morice K. Spasticity. [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507869/
  • Antispasmodic drugs. These medications stop the spontaneous or involuntary contraction of muscles (such as jerks, twitches, or cramps) that cause spasms. 3 Conermann T, Christian D. Carisoprodol. [Updated 2022 Nov 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK553077/

Two medications, tizanidine and diazepam, have both antispastic and antispasmodic activity. 5 Rivelis Y, Zafar N, Morice K. Spasticity. [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507869/

How Muscle Relaxers May Be Given

Muscle relaxers are given orally (by mouth) or via an injection, and in rare cases, the drug is delivered directly into the spinal cord through an implanted device. 6 Kim J, De Jesus O. Medication Routes of Administration. [Updated 2023 Feb 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK568677/

An oral muscle relaxer is more commonly prescribed because it is convenient to take and does not require needles. 7 Ghanavatian S, Derian A. Baclofen. [Updated 2022 Dec 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526037/

Underlying medical conditions and the severity and expected duration of pain and/or disability may be reasons to consider an injectable form. 7 Ghanavatian S, Derian A. Baclofen. [Updated 2022 Dec 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526037/

Oral administration of muscle relaxers

Oral muscle relaxers are taken by mouth in the form of a tablet or capsule. As the drug moves through the gastrointestinal tract, it is slowly absorbed into the bloodstream and delivered to the brain and other areas of the body. 7 Ghanavatian S, Derian A. Baclofen. [Updated 2022 Dec 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526037/

Intramuscular (IM) administration of muscle relaxers

IM injection involves delivering medication into a large muscle with a lot of blood vessels, such as the thigh or buttock muscle. The medication is slowly absorbed into the bloodstream and then delivered throughout the body. 7 Ghanavatian S, Derian A. Baclofen. [Updated 2022 Dec 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526037/

IM muscle relaxers are typically used in emergency or urgent care settings when a quick onset of action is preferred. They are also used when a person has difficulty swallowing. 7 Ghanavatian S, Derian A. Baclofen. [Updated 2022 Dec 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526037/

Intravenous (IV) administration of muscle relaxers

IV injection delivers the drug through a vein and directly into the bloodstream. This method allows the medication to travel quickly to the brain and other areas of the body and provides quick relief. 7 Ghanavatian S, Derian A. Baclofen. [Updated 2022 Dec 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526037/

Intravenous muscle relaxers are reserved for use in a hospital or other clinical setting. 7 Ghanavatian S, Derian A. Baclofen. [Updated 2022 Dec 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526037/

Intrathecal (IT) administration of muscle relaxers

The intrathecal route involves delivering medication directly into the fluid surrounding the spinal cord, typically through an implanted pain pump. 7 Ghanavatian S, Derian A. Baclofen. [Updated 2022 Dec 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526037/  The intrathecal route uses a smaller dose of medication, causing fewer or less intense side effects. 7 Ghanavatian S, Derian A. Baclofen. [Updated 2022 Dec 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526037/

Intrathecal muscle relaxers are generally only used in cases of severe spasticity from an underlying chronic condition such as cerebral palsy. 8 Drugs@FDA: FDA-Approved Drugs. www.accessdata.fda.gov

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Common Muscle Relaxers and Their Effects

The following table lists the commonly prescribed muscle relaxers, the types of muscle issues they treat, and the mode of delivery.

Medication Antispastic Antispasmodic Mode of Delivery 8 Drugs@FDA: FDA-Approved Drugs. www.accessdata.fda.gov
Baclofen (Lioresal) 9 Baclofen. Package Insert. Advagen Pharma Limited; 2023 ✓   Oral, intrathecal (IT)
Dantrolene (Dantrium) 10 Dantrolene. Package Insert. Amneal Pharmaceuticals of New York LLC; 2022 ✓   Oral, intravenous (IV)
Tizanidine (Zanaflex) 11 Tizanidine. Package Insert. Advagen Pharma Limited; 2020 ✓ ✓ >Oral
Diazepam (Valium) 12 Diazepam. Package Insert. Mayne Pharma Commercial LLC; 2023 ✓ ✓ Oral, intravenous (IV), intramuscular (IM)
Carisoprodol (Soma) 13 Soma. Package Insert. Meda Pharmaceuticals Inc; 2023   ✓ Oral
Chlorzoxazone 14 Chlorzoxazone. Package Insert. Aurobindo Pharma Limited; 2022   ✓ Oral
Cyclobenzaprine (Amrix) 15 Cyclobenzaprine. Package Insert. Rising Health, LLC; 2020   ✓ Oral
Metaxalone 16 Metaxalone. Package Insert. Amneal Pharmaceuticals LLC; 2022   ✓ Oral
Methocarbamol (Robaxin) 17 Methocarbamol. Package Insert. Granules Pharmaceuticals Inc.; 2023   ✓ Oral, intravenous (IV), intramuscular (IM)
Orphenadrine 18 Orphenadrine. Package Insert. Amneal Pharmaceuticals of New York LLC; 2019   ✓ Oral, intravenous (IV), intramuscular (IM)

Antispasmodic muscle relaxers are more frequently prescribed for back and neck pain compared to antispastics. 2 Cashin AG, Folly T, Bagg MK, et al. Efficacy, acceptability, and safety of muscle relaxants for adults with non-specific low back pain: systematic review and meta-analysis. BMJ. 2021;374:n1446. Published 2021 Jul 7. doi:10.1136/bmj.n1446

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When Muscle Relaxers May Be Prescribed for Back and Neck Pain

Muscle strain or ligament sprain is a common indication for muscle relaxants.

Muscle relaxers are prescribed when muscle spasms or spasticity are suspected as the cause of the pain, such as in cases of 1 Barreto TW, Lin KW. Noninvasive Treatments for Low Back Pain. American Family Physician. 2017;96(5):324-327. Accessed August 14, 2023. https://www.aafp.org/pubs/afp/issues/2017/0901/p324.html :

The effectiveness of muscle relaxers differs for each person. 19 Qaseem A, Wilt TJ, McLean RM, et al. Noninvasive Treatments for Acute, Subacute, and Chronic Low Back Pain: A Clinical Practice Guideline From the American College of Physicians. Ann Intern Med. 2017;166(7):514-530. doi:10.7326/M16-2367 Factors such as the underlying cause of pain and the use of other OTC or non-drug therapies play a role in the overall effectiveness of the treatment. 2 Cashin AG, Folly T, Bagg MK, et al. Efficacy, acceptability, and safety of muscle relaxants for adults with non-specific low back pain: systematic review and meta-analysis. BMJ. 2021;374:n1446. Published 2021 Jul 7. doi:10.1136/bmj.n1446

Safety Profile of Muscle Relaxers

Muscle relaxers are generally safe and well-tolerated when used short-term at recommended doses. 2 Cashin AG, Folly T, Bagg MK, et al. Efficacy, acceptability, and safety of muscle relaxants for adults with non-specific low back pain: systematic review and meta-analysis. BMJ. 2021;374:n1446. Published 2021 Jul 7. doi:10.1136/bmj.n1446

Sedation and drowsiness are the most commonly reported side effects, but factors such as underlying conditions and the use of other medications may increase the risk. 9 Baclofen. Package Insert. Advagen Pharma Limited; 2023 - 18 Orphenadrine. Package Insert. Amneal Pharmaceuticals of New York LLC; 2019

It is advisable to discuss the potential side effects and risks with a doctor.

Kathee de Falla

Dr. Kathee de Falla is a licensed and certified pharmacist. She has more than a decade of experience providing medical advice and supplying prescription medications in a retail setting. Dr. de Falla spent several years developing drugs at Abbott Laboratories, a pharmaceutical company where she holds a patent for a drug formulation.

  • 1 Barreto TW, Lin KW. Noninvasive Treatments for Low Back Pain. American Family Physician. 2017;96(5):324-327. Accessed August 14, 2023. https://www.aafp.org/pubs/afp/issues/2017/0901/p324.html
  • 2 Cashin AG, Folly T, Bagg MK, et al. Efficacy, acceptability, and safety of muscle relaxants for adults with non-specific low back pain: systematic review and meta-analysis. BMJ. 2021;374:n1446. Published 2021 Jul 7. doi:10.1136/bmj.n1446
  • 3 Conermann T, Christian D. Carisoprodol. [Updated 2022 Nov 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK553077/
  • 4 Li Y, Delcher C, Reisfield GM, Wei YJ, Brown JD, Winterstein AG. Utilization Patterns of Skeletal Muscle Relaxants Among Commercially Insured Adults in the United States from 2006 to 2018. Pain Med. 2021;22(10):2153-2161. doi:10.1093/pm/pnab088
  • 5 Rivelis Y, Zafar N, Morice K. Spasticity. [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507869/
  • 6 Kim J, De Jesus O. Medication Routes of Administration. [Updated 2023 Feb 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK568677/
  • 7 Ghanavatian S, Derian A. Baclofen. [Updated 2022 Dec 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526037/
  • 8 Drugs@FDA: FDA-Approved Drugs. www.accessdata.fda.gov
  • 9 Baclofen. Package Insert. Advagen Pharma Limited; 2023
  • 10 Dantrolene. Package Insert. Amneal Pharmaceuticals of New York LLC; 2022
  • 11 Tizanidine. Package Insert. Advagen Pharma Limited; 2020
  • 12 Diazepam. Package Insert. Mayne Pharma Commercial LLC; 2023
  • 13 Soma. Package Insert. Meda Pharmaceuticals Inc; 2023
  • 14 Chlorzoxazone. Package Insert. Aurobindo Pharma Limited; 2022
  • 15 Cyclobenzaprine. Package Insert. Rising Health, LLC; 2020
  • 16 Metaxalone. Package Insert. Amneal Pharmaceuticals LLC; 2022
  • 17 Methocarbamol. Package Insert. Granules Pharmaceuticals Inc.; 2023
  • 18 Orphenadrine. Package Insert. Amneal Pharmaceuticals of New York LLC; 2019
  • 19 Qaseem A, Wilt TJ, McLean RM, et al. Noninvasive Treatments for Acute, Subacute, and Chronic Low Back Pain: A Clinical Practice Guideline From the American College of Physicians. Ann Intern Med. 2017;166(7):514-530. doi:10.7326/M16-2367

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