Baclofen, sold under the brand name Lioresal among others, is a medication used to treat muscle spasticity, such as from a spinal cord injury or multiple sclerosis.

[14] The adverse effects and safety profile associated with baclofen when it is combined with sedative drugs (for example alcohol or benzodiazepines) range depending on the dose and the individual.

[18][19] Baclofen is primarily used for the treatment of spastic movement disorders, especially in instances of spinal cord injury, and multiple sclerosis.

[20] Intrathecal baclofen is used for severe spasticity of spinal cord origin, that is refractive to maximum doses of oral antispasmodic agents, or who experience intolerable side effects.

[23] Adverse effects include drowsiness, dizziness, weakness, fatigue, headache, trouble sleeping, nausea and vomiting, poor concentration and recall (resembling dementia), urinary retention, or constipation.

Withdrawal symptoms are more likely if baclofen is administered intrathecally or for long periods of time (more than a couple of months) and can occur from low or high doses.

[25] Withdrawal symptoms may include auditory hallucinations, visual hallucinations, tactile hallucinations, delusions, confusion, agitation, delirium, disorientation, fluctuation of consciousness, insomnia, dizziness, nausea, inattention, memory impairments, perceptual disturbances, itching, anxiety, depersonalization, hypertonia, hyperthermia (higher than normal temperature without infection), formal thought disorder, psychosis, mania, mood disturbances, restlessness, and behavioral disturbances, tachycardia, seizures, tremors, autonomic dysfunction, hyperpyrexia (fever), extreme muscle rigidity resembling neuroleptic malignant syndrome and rebound spasticity.

[27] Reports of overdose indicate that baclofen may cause symptoms including vomiting, general weakness, sedation, respiratory insufficiency, seizures, dizziness,[3] headaches,[3] itching, hypothermia, bradycardia, cardiac conduction abnormalities, hypertension, hyporeflexia and coma sometimes mimicking brain death.

Baclofen is postulated to block mono-and-polysynaptic reflexes by acting as an inhibitory ligand, inhibiting the release of excitatory neurotransmitters.

[35] Moreover, baclofen is in the range of 100-fold more potent by weight as an agonist of the GABAB receptor in comparison to phenibut, and in accordance, is used at far lower relative dosages.

[40][41] In his 2008 book, Le Dernier Verre (translated literally as The Last Glass or The End of My Addiction), French-American cardiologist Olivier Ameisen described how he treated his alcoholism with baclofen.

Inspired by this book, an anonymous donor gave $750,000 to the University of Amsterdam in the Netherlands to initiate a clinical trial of high-dose baclofen, which Ameisen had called for since 2004.

[42] The researchers concluded, "In summary, the current study did not find evidence of a positive effect of either low or high doses of baclofen in AD patients.

However, we cannot exclude the possibility that baclofen is an effective medication for the treatment of severe, heavy drinking AD patients not responding to or not accepting routine psychosocial interventions.

"[43] Baclofen can be administered, orally, intrathecally (directly into the cerebral spinal fluid) using a pump implanted under the skin, or transdermally as part of a pain-relieving and muscle-relaxing topical cream mix (also containing gabapentin and clonidine) prepared at a compounding pharmacy.

[13][44] Intrathecal pumps offer much lower doses of baclofen because they are designed to deliver the medication directly to the spinal fluid rather than going through the digestive and blood system first.

[44] Besides those with spasticity, intrathecal administration is also used in patients with cerebral palsy[44] or multiple sclerosis who have severe painful spasms which are not controllable by oral baclofen.