Baclofen

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 is a potent GABAB receptor agonist, antispasmodic, and skeletal muscle relaxant used to treat chronic muscle spasms and muscle spasticity, such as from a spinal cord injury or multiple sclerosis. It may also be used for hiccups and muscle spasms near the end of life, and off-label to treat alcohol use disorder or opioid withdrawal symptoms. It is taken orally or by intrathecal pump (delivered into the spinal canal via an implantable pump device). Baclofen should be avoided in the setting of chronic kidney disease and end stage renal disease as even small doses can cause excessive toxicity. Common side effects include sleepiness, weakness, and dizziness. Serious side effects, such as seizures and rhabdomyolysis, may occur if use of baclofen is stopped abruptly. Use during pregnancy is of unclear safety, whilst use during breastfeeding is likely safe, and even more so if oral administration is avoided. The adverse effects and safety profile associated with baclofen when it is combined with sedative drugs (e.g., alcohol, barbiturates, and benzodiazepines) range depending on the dose and the individual. The interaction may increase the sedative effects of all ingested sedatives and as such is not generally recommended. In high doses the interaction with alcohol can cause de novo seizures. Baclofen was approved for medical use in the United States in 1977. It is available as a generic medication. It is on the World Health Organization's List of Essential Medicines. In 2023, it was the 87th most commonly prescribed medication in the United States, with more than 7 million prescriptions.