Baclof 20
(BACLOFEN 20mg extended released)

Drug Effects

Chemical Formula


C10H12ClNO2

Iupac Name


(RS)-4-amino-3-(4-chlorophenyl)butanoic acid

Usage


Baclofen is analogue of gamma aminobutyric acid used as a muscle relaxant and antispastic. Chemically Baclofen is identified as ß-(aminomethyl)-p-chlorohydrocinnamic acid. It relaxes muscles and relieves pain and discomfort due to certain nerve disorders.Baclofen is used in the treatment of multiple sclerosis, spinal cord diseases etc. Administered orally.

Baclofen is primarily indicated in conditions like Hiccup due to gastric distension in palliative care, Hiccup in palliative care, Male hypersexuality, Muscle spasm in palliative care, Parkinson's disease (but not drug-induced extrapyramidal symptoms), Spasticity, and can also be given in adjunctive therapy as an alternative drug of choice in Hiccup,Neurogenic bladder, Refractory trigeminal neuralgia.

Adverse Effect


Sedation, drowsiness, ataxia, dizziness, headache, confusion, hallucinations, skin reactions, GI symptoms, enuresis.

Potentially Fatal: Respiratory or CV depression, seizures.

Mechanism Action


Baclofen is a direct agonist at GABAB receptors. The precise mechanism of action of Baclofen is not fully known. It is capable of inhibiting both monosynaptic and polysynaptic reflexes at the spinal level, possibly by hyperpolarization of afferent terminals, although actions at supraspinal sites may also occur and contribute to its clinical effect.

Precaution


Baclofen should be used with caution in patients with medical history especially of diabetes, kidney problems, seizures, psychiatric or brain disorders (e.g. stroke), ulcers and of any drug allergy. Because this drug may cause dizziness or drowsiness, use with caution while driving or performing tasks that require alertness. Limit alcohol consumption as it may increase the drowsiness or dizziness effects of this drug. It should be used with caution in elderly patients. This drug should be used only if clearly needed during pregnancy or lactation.

Drug Interaction


Hypotensive effect may be increased with antihypertensives. Concomittant use with levodopa in Parkinson patients may result in confusion, agitation, hallucinations.


Potentially Fatal: CNS depressants and alcohol may potentiate CNS effects.

Pregnancy Category


Category C:

Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.

Absorption


Rapidly and almost completely absorbed from GIT (oral); peak plasma conc after 1-3 hr.

Distribution


Blood-brain barrier, CSF (equivalent to 12% conc found in plasma). Protein-binding: 30%.

Metabolism


Hepatic (15% of the dose).

Elemination


Via urine (70-80% as unchanged drug); elimination half-life (Via urine (70-80% as unchanged drug)

References


  1. Dzitoyeva S, Dimitrijevic N, Manev H: Gamma-aminobutyric acid B receptor 1 mediates behavior-impairing actions of alcohol in Drosophila: adult RNA interference and pharmacological evidence. Proc Natl Acad Sci U S A. 2003 Apr 29;100(9):5485-90. Epub 2003 Apr 11. 
  2. Mezler M, Muller T, Raming K: Cloning and functional expression of GABA receptors from Drosophila. Eur J Neurosci. 2001 Feb;13(3):477-86. 
  3. See S, Ginzburg R: Skeletal muscle relaxants. Pharmacotherapy. 2008 Feb;28(2):207-13.