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. Learn about the side effects of baclofen, from common to rare, for consumers and healthcare professionals. 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. 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. 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 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, 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). Baclofen oral tablet is used to treat muscle spasms. Learn about side effects, warnings, dosage, and more. NHS information about the medicine baclofen, including what it's used for, who can take it, how to take it and side effects. 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.