API: Baclofen

What Is Baclofen and How Does It Work?

Baclofen is a central nervous system depressant that is commonly used as a skeletal muscle relaxant and antispasmodic. The drug works by inactivating reflexes at the spinal level, thereby blocking the release of excitatory neurotransmitters. Baclofen, chemically described as 4-amino-3-(-4-chlorophenyl)-butanoic acid, is FDA-approved to treat reversible spasticity in patients with spinal cord disease or multiple sclerosis(MS), and may also relieve muscle pain and stiffness.

For more information, including a MSDS sheet, please see PNA’s Baclofen page.

Approved Indications

Multiple Sclerosis: Patients with MS suffer from an immune system that attacks the myelin sheath covering nerve fibers. MS-based spasticity causes muscles to remain in a contracted state by disrupting communications between nerve cells that would allow the muscles to relax.1 Baclofen is the first-line treatment and works by reducing the number of communications that contract muscles in the first place.

Spinal Cord Spasticity: Baclofen can similarly treat spasticity of spinal cord origin, whether the symptoms derive from disease or injury.

Important Information: Note that baclofen is NOT indicated for treating skeletal muscle spasms that originate from rheumatic disorders.

Side Effects and Drug Interactions

Common side effects in patients taking baclofen include2:

  • Drowsiness and fatigue
  • Headaches
  • Seizures
  • Nausea and vomiting
  • Low blood pressure
  • Constipation and irregularities in urination
  • Insomnia
  • Confusion

Baclofen should not be discontinued without medical advice. Abrupt discontinuation may cause seizures and hallucinations, as well as high fever, returning spasticity and muscle stiffness, and rhabdomyolysis.

Patients who suffer from bloody urine, painful urination, trouble maintaining an erection, rashes, or irritation in the stomach or bowels should contact their pharmacist or physician immediately.

Patients who are allergic to baclofen should not take this medication. Patients suffering from renal dysfunction, autonomic dysreflexia, psychoses, or seizure disorders may be at risk for severe side effects from this drug.3

Medications known to have major interactions with baclofen include acetaminophen, buprenorphine, propoxyphene, sodium oxybate, and naloxone.

Latest News and Research

Baclofen was developed in the UK in 1966 and brought relief to some 12 million people worldwide who suffered from muscle spasms, lower limb weakness, impaired bladder, and severe drowsiness caused by treatment at the time.4 For many years, baclofen has been the number one treatment for muscle spasticity in MS patients, as well as those suffering from spinal cord conditions. However, the muscle weakness caused by baclofen treatment has caused older patients who need walkers and canes to look to gabapentin for spasticity treatment.

New studies show that not only is baclofen a superior treatment to gabapentin and more recently, clonazepam, but baclofen treatment via intrathecal pump is a particularly powerful alternative. The pump requires lower doses of baclofen, resulting in reduction of muscle weakness and improved ability to perform daily routine tasks.5 The pump also has potential for controlling spasms in children with cerebral palsy.6

Baclofen may be used to treat alcohol dependence in adults, although this treatment is the subject of much controversy due to the high levels of drug needed, the probable concomitance of other severe diseases or conditions, and the need for in-depth physician supervision.7

Buying Guide

PNA is a recommended bulk supplier of Baclofen and other APIs. You can learn more about Baclofen here.

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Show 7 footnotes

  1. “Baclofen,” February 8, 2013, https://www.mstrust.org.uk/a-z/baclofen
  2. “Baclofen Side Effects Center,” April 17, 2015, http://www.rxlist.com/baclofen-side-effects-drug-center.htm
  3. “Baclofen Drug Interactions,” December 1, 2015, http://www.drugs.com/drug-interactions/baclofen.html
  4. “Baclofen — from standard treatment for spasticity to managing alcoholism,” June 12, 2013, http://www.pharmaceutical-journal.com/news-and-analysis/features/baclofen-from-standard-treatment-for-spasticity-to-managing-alcoholism/11122223.article
  5. “Baclofen Pump Therapy for the Treatment of Spasticity,” August 22, 2013, http://www.med.umich.edu/1libr/PMR/BaclofenPumpTherapy.pdf
  6. “Efficacy of intrathecal baclofen therapy in children with intractable spastic cerebral palsy: A randomised controlled trial,” May 2009, http://www.ejpn-journal.com/article/S1090-3798(08)00095-0/abstract?cc=y=
  7. “The use of very high-doses of baclofen for the treatment of alcohol-dependence: a case series,” October 10, 2014, “http://journal.frontiersin.org/article/10.3389/fpsyt.2014.00143/full