What are muscle relaxants?
Muscle relaxants are prescription medicines that can help with muscle spasms, muscle stiffness, muscle pain and spasticity. They do not all work in the same way, and one medicine may not be suitable for every type of pain.
Some medicines are intended for acute muscle spasm after a sprain, strain or other injury. Others, such as baclofen, are mainly used for long-term muscle spasticity linked to conditions affecting the nervous system.
What causes muscle spasms?
Muscle spasms can happen when a muscle suddenly tightens and does not relax normally. Common causes include:
Muscle strain, sprain or overuse
Poor posture or long periods of sitting
Back or neck problems
Sports injuries
Nerve compression
Multiple sclerosis or cerebral palsy
Stroke, brain injury or spinal cord injury
Dehydration or changes in minerals
Some medicines and medical conditions
A recurring or severe spasm should be assessed because treating the pain alone may not correct the underlying cause.
Muscle spasm symptoms
Possible symptoms include:
Sudden tightening or cramping
Pain when moving
Stiffness or reduced flexibility
A hard or knotted feeling in the muscle
Shaking or involuntary movement
Muscle weakness
Pain in the back, neck, shoulder, arms or legs
Seek medical advice when spasms keep returning, affect walking or daily activities, or occur with numbness, weakness or loss of bladder or bowel control.
Muscle relaxant medicines in this category
The active ingredient is more important than the brand name. Product formulas and approvals can vary between countries, so check the ingredient, strength, dosage form and prescription status before ordering.
Baclofen medicines: Baclofen is an antispastic medicine used mainly for muscle spasticity caused by conditions affecting the brain, spinal cord or nerves. Products in this group include BACLOF OD 20MG, BACLOHEAL 10MG, BACLOHEAL 25MG, BACLOSIGN 10MG, BACLOSIGN 25MG, LIOFEN 10MG and LIOFEN XL 20MG. Baclofen may reduce abnormal muscle signals and help improve movement. It is not automatically the right choice for ordinary back pain or every muscle ache.
Cyclobenzaprine medicines: Cyclobenzaprine is generally used for short-term painful muscle spasms linked to acute musculoskeletal problems. Products in this group include CYCLOBENZ ER 15MG, CYCLOBENZ ER 30MG, CYCLOBOON ER 15MG, CYCLOBOON ER 30MG, FLEXABENZ 5MG and FLEXABENZ ER 15MG. Extended-release tablets or capsules should be swallowed as directed. Do not crush or alter them unless a pharmacist or doctor confirms that it is safe.
Carisoprodol medicines: CARIDOLL 500MG and CARIDOLL 750MG contain carisoprodol. Carisoprodol may be prescribed for acute muscle pain and spasms, usually for a limited period. It can cause sleepiness and has a higher risk of misuse, dependence and withdrawal than many other muscle relaxants.
Metaxalone medicines: FLEXURA 400MG contains metaxalone. It may be used with rest and physical therapy for painful muscle spasms caused by strains, sprains or other musculoskeletal injuries. FLEXPAS 15MG is also listed in this category. The active ingredient should be confirmed from the product label before publishing a salt-specific description or comparing it with another medicine.
Secondary treatment and recovery support
Medicine is only one part of muscle spasm treatment. Depending on the cause, a healthcare professional may also recommend:
Rest during the early stage of an injury
Heat or cold packs
Gentle stretching
Physiotherapy
Posture correction
Gradual strengthening exercises
Treatment for nerve, joint or spinal conditions
Pain relievers or anti-inflammatory medicines may sometimes be used with a muscle relaxant. They are not interchangeable, and combining medicines should only be done with professional advice.
Muscle relaxant side effects
Common muscle relaxant side effects include drowsiness, dizziness, tiredness, weakness, headache, nausea, dry mouth, blurred vision and reduced concentration. Avoid driving, cycling or operating machinery until the effect of the medicine is known.
Serious problems can include fainting, severe confusion, breathing difficulty, an allergic reaction, hallucinations, seizures or loss of consciousness. Seek urgent help if these symptoms occur or if too much medicine has been taken.
Muscle relaxant interactions and precautions
Do not mix muscle relaxants with alcohol, opioids, sleeping tablets, benzodiazepines or other medicines that cause drowsiness unless a healthcare professional approves the combination. The combined effect can slow breathing and increase the risk of falls or overdose.
Tell the prescriber about kidney or liver disease, epilepsy, pregnancy, breastfeeding, mental health conditions and any history of alcohol or drug dependence. Baclofen should not be stopped suddenly after regular use because withdrawal can cause severe spasms, confusion, fever, hallucinations or seizures.