A to Z of MS Baclofen

Product names

Lioresal, Lyflex

Baclofen is a drug that has a long history of use as a treatment for spasticity and spasms in MS. The NICE Guideline suggests that baclofen should be the first drug used when treating spasticity.

How baclofen works

When someone experiences spasticity, the affected muscles remain in the contracted 'on' state as the balancing message to relax ('off') is interrupted or blocked by the damage caused by MS. Baclofen is a type of drug known as a gamma aminobutyric acid (GABA)-B receptor agonist, which means that it affects the transmission of messages between nerve cells. This reduces the transmission of the messages causing muscles to contract.

How is baclofen given?

Baclofen is taken orally, either as a tablet or as a liquid. Medication can be increased in steps until the desired effect is achieved or side effects become a problem. For people with more advanced spasticity, the drug can be administered directly into the spine (intrathecally) using an implanted pump.

Side effects and contraindications

Side effects affect about 45% of people taking baclofen. These include drowsiness, fatigue, dizziness and difficulty sleeping. If the dose is too high, muscle tone can be reduced too much leading to weakness. Abrupt discontinuation may result in severe withdrawal symptoms, which include hallucinations and seizures, so discontinuation of treatment requires the gradual reduction of the daily dose.

Reference

Sachais BA, et al.
Baclofen, a new antispastic drug. A controlled, multicenter trial in patients with multiple sclerosis.
Archives of Neurology 1977;34(7):422-428.
abstract

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