Brand name Lioresal.
A central nervous system depressant used as a skeletal muscle relaxant.
A centrally acting gamma-amino butyric acid beta agonist.
It is primarily used to treat muscle spasticity.
Also prescribed off-label for alcoholism, gastroesophageal reflux disease, nystagmus, and trigeminal neuralgia.
It is indicated for spasticity resulting from multiple sclerosis.
Also used in topical creams to help with pain.
Pregnancy category US: C.
Routes of administration are oral, and intrathecal.
Bioavailability well absorbed.
Protein binding 30%.
Metabolism 85% excreted in urine/feces unchanged.
15% metabolized by deamination
Biological half-life 1.5 to 4 hours.
Excretion renal 70–80%.
It is a GABA receptor agonist, specifically of the GABAB receptors.
It helps, restore the GABA supply, which is chronically depleted in alcohol use disease.
Acts as a GABA agonist at GABAB receptors in the brain and spinal cord, resulting in hyperpolarization of neurons expressing this receptor, most likely due to increased potassium ion conductance.
Inhibits neural function presynaptically, by reducing calcium ion influx, and thereby reducing the release of excitatory neurotransmitters in both the brain and spinal cord.
It may also reduce pain in patients by inhibiting the release of substance P in the spinal cord, as well.
Its beneficial effects in spasticity result from actions at spinal and supraspinal sites.
A derivative of γ-aminobutyric acid (GABA).
Tolerance to its muscle-related therapeutic benefits does not seem to occur to a significant degree.
It retains its therapeutic anti-spasmodic effects even after many years of continued use.
Tolerance may develop in some people receiving intrathecal baclofen treatment.
Primarily used for the treatment of spastic movement disorders, especially in instances of spinal cord injury, cerebral palsy, and multiple sclerosis.
It is used to treat Tourette’s syndrome or tardive dyskinesia.
Use in stroke or Parkinson’s disease is not recommended.
Evidence is promising that it may help with alcohol withdrawal syndrome.
Discontinuation of baclofen can be associated with a withdrawal syndrome.
Withdrawal symptoms are more likely if the drug is used for long periods of time.
Withdrawal symptoms are drug dose independent.
The severity of withdrawal depends on the rate at which it is discontinued, so the the dose should be tapered down slowly.
Withdrawal symptoms include: hallucinations, delusions, confusion, agitation, delirium, disorientation, fluctuation of consciousness, insomnia, dizziness, nausea, inattention, memory impairments, perceptual disturbances, pruritus/itching, anxiety, depersonalization, hypertonia, hyperthermia, formal thought disorder, psychosis, mania, mood disturbances, restlessness, and behavioral disturbances, tachycardia, seizures, tremors, autonomic dysfunction, fever, extreme muscle rigidity resembling neuroleptic malignant syndrome and rebound spasticity.
May suppress psychomotor skills.
Does not produce euphoria or other pleasant effects.
Does not possess addictive properties, and has not been associated with any degree of drug craving.
Use among patients with chronic kidney disease, may be associated with an increased risk of encephalopathy.
Overdose may cause symptoms including vomiting, weakness, sedation, somnolence, respiratory depression, seizures, unusual pupil size, dizziness, headaches, itching, hypothermia, bradycardia, hypertension, hyporeflexia, coma, and death.
Activates the GABAB receptor.
Postulated to block mono-and-polysynaptic reflexes by acting as an inhibitory neurotransmitter, blocking the release of excitatory transmitters.
Does not have significant affinity for the GHB receptor.
Has no known abuse potential.
The modulation of the GABAB receptor is what produces baclofen’s range of therapeutic properties.
Similarly to phenibut and pregabalin which are close analogues of baclofen
The drug is rapidly absorbed after oral administration
Widely distributed throughout the body.
Biotransformation is low.
Predominantly excreted unchanged by the kidneys.
The half life roughly 2–4 hours, and needs to be administered frequently throughout the day to control spasticity appropriately.
When used intrathecally it treats spasticity due to many conditions.
Baclofen 20 mg oral tablet, and can be administered transdermally as part of a pain-relieving and muscle-relaxing cream mix at a compounding pharmacy.
Can be given intrathecally using a pump implanted under the skin.
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.
Intrathecal pumps are often preferred in spasticity patients, as very little of the oral dose actually reaches the spinal fluid.
Intrathecal administration is also used in patients with multiple sclerosis who have severe painful spasms which are not controllable by oral medicine.