Baclofen, sold under the brand name Lioresal among others, is a central nervous system (CNS) depressant and derivative of the inhibitory neurotransmitter, gamma -Aminobutyric acid (GABA). Key facts Baclofen reduces pain and discomfort caused by muscle spasms. The tablets and liquid start to work after 1 hour after taking it. However, it might take a few days before you find the right dose to control your symptoms. Common side effects include feeling sleepy and feeling sick (nausea). Baclofen is in a class of medications called skeletal muscle relaxants. Baclofen acts on the spinal cord nerves and decreases the number and severity of muscle spasms caused by multiple sclerosis or spinal cord conditions. It also relieves pain and improves muscle movement. Baclofen is a muscle relaxant used to treat spasticity and muscle pain in conditions like multiple sclerosis and spinal cord injuries by easing nerve signals. What is this medication? BACLOFEN (BAK loe fen) treats muscle spasms. It works by relaxing your muscles, which reduces muscle stiffness. It belongs to a group of medications called muscle relaxants. Baclofen is used to help relax certain muscles in your body. It relieves the spasms, cramping, and tightness of muscles caused by medical problems, including multiple sclerosis or certain injuries to the spine. Find patient medical information for Baclofen (Lioresal, Fleqsuvy, and others) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Easy-to-read patient tips for baclofen covering how it works, benefits, risks, and best practices. Baclofen is a muscle relaxer. It's used to treat muscle spasms from multiple sclerosis or spinal cord injuries in adults and children ages 12 years and older. This medication is taken by mouth, typically 3 times a day. Baclofen is a muscle relaxant and antispastic used for treating spasm of skeletal muscles, muscle clonus, rigidity, and pain caused by multiple sclerosis. Baclofen is also injected into the spinal cord to treat severe spasticity, spinal cord injuries, and other spinal cord diseases.