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Baclofen: 7 things you should know

Medically reviewed by Carmen Pope, BPharm. Last updated on March 31, 2023.

1. How it works

  • Baclofen may be used as a muscle relaxant.
  • Experts are not sure exactly how baclofen works to relieve muscle spasms but research suggests it inhibits nerve impulses in the spine, which relaxes and relieves muscle contractions.
  • Baclofen belongs to the class of medicines known as skeletal muscle relaxants.

2. Upsides

  • Baclofen is used to relieve muscle spasms such as those caused by multiple sclerosis or spinal cord injuries due to damage or disease.
  • Particularly effective for relieving flexor spasms (involuntary muscle spasms involving the ankle, knee, or hip) and the pain, contractions, and rigidity associated with these.
  • May help restore some muscle function.
  • Baclofen is not effective for muscle spasms caused by rheumatoid arthritis, cerebral palsy, stroke, or Parkinson's disease.
  • May also be used off-label to treat other conditions such as hiccups or Tourette's syndrome.
  • Generic baclofen is available.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Drowsiness, dizziness, or sedation, that may affect your ability to drive or operate machinery or perform other hazardous tasks. The sedative effect of baclofen may be enhanced by alcohol or by other medications that also cause sedation (such as benzodiazepines and opiates).
  • Weakness, fatigue, insomnia, nausea, constipation, low blood pressure, headache, and confusion have also been reported.
  • Sudden discontinuation of baclofen has been associated with hallucinations and seizures. Baclofen should be withdrawn slowly unless it is an emergency.
  • May not be suitable for some people, including those with a history of stroke or who rely on spasticity to maintain an upright position, balance, or for increased function. The dosage of baclofen should be reduced in those with kidney disease.
  • People with a history of seizures or epilepsy should be monitored regularly for changes in seizure control or EEG recordings.
  • Neonatal withdrawal symptoms, such as increased muscle tone, tremors, jitteriness, or seizures have been reported starting hours to days after delivery in neonates whose mothers were treated with oral baclofen throughout pregnancy. If the potential benefit of using baclofen during pregnancy justifies the potential risk to the fetus then gradually reduce the dose and discontinue baclofen before delivery. Baclofen appears in low levels in milk but is not expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. Monitor newborn infants for signs of sedation.
  • May cause an increase in the risk of ovarian cysts.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Baclofen relieves muscle spasms associated with multiple sclerosis and spinal cord injury or disease, but its use is limited by its ability to cause sedation and increase seizure risk.

5. Tips

  • Baclofen may be taken with or without food.
  • Treatment should be started at a low dose and increased gradually as directed by your doctor. Take baclofen as directed by your doctor. Do not take more than is recommended.
  • Do not drive or operate machinery, or perform hazardous tasks if baclofen makes you drowsy, dizzy, or sleepy.
  • Avoid alcohol while you are taking baclofen.
  • Do not stop taking this medicine suddenly. If you feel you are not gaining any benefit from this drug, or the side effects are intolerable, talk with your doctor about slowly discontinuing it.
  • Tell your doctor if you are pregnant, intending to become pregnant, or breastfeeding because baclofen may not be suitable for you.

6. Response and effectiveness

  • Baclofen is rapidly absorbed, although absorption may be reduced with higher dosages. There is a wide variation in the way individuals respond to baclofen, with some people reporting a reduction in symptoms of muscle spasm within a few hours, whereas for some others it may take several weeks.

7. Interactions

Medicines that interact with baclofen may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with baclofen. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with baclofen include:

  • anti-anxiety medications
  • anticonvulsants
  • antidepressants, such as amitriptyline, imipramine, nortriptyline, and monoamine oxidase inhibitors
  • antihistamines that cause sedation, such as diphenhydramine
  • opioid analgesics such as oxycodone and morphine
  • other muscle relaxants such as cyclobenzaprine
  • sleeping pills
  • some medications used to treat mental illness, such as clozapine and thioridazine.

Alcohol may worsen the side effects of baclofen such as drowsiness and dizziness.

Note that this list is not all-inclusive and includes only common medications that may interact with baclofen. You should refer to the prescribing information for baclofen for a complete list of interactions.


Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use baclofen only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2023 Revision date: March 30, 2023.