Baclofen information from DrugsUpdate
P - Caution when used during pregnancy
Baclofen (brand names Kemstro and Lioresal) is a derivative of gamma-aminobutyric acid (GABA) primarily used to treat spasticity. It is an agonist specific to mammalian but not fruit fly (Drosophila) GABAB receptors. Its beneficial effects result from actions at spinal and supraspinal sites. Baclofen can also be used to treat hiccups. It has been shown to prevent rises in body temperature induced by the drug MDMA in rats. A very beneficial property of baclofen is that tolerance does not seem to occur to any significant degree in that baclofen retains its therapeutic anti-spasmodic effects even after many years of chronic use.
Pharmacodynamics
Pharmacokinetics
Baclofen is an antispastic. It inhibits both monosynaptic and polysynaptic reflexes at spinal level.
Absorption Rapidly and almost completely absorbed from the GI tract (oral); peak plasma concentrations 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).
Excretion Via urine (70-80% as unchanged drug); elimination half-life: 3-4 hr (plasma), 5 hr (CSF).
Baclofen Indications / Baclofen Uses
Information Not Available
Baclofen Adverse Reactions / Baclofen Side Effects
Sedation, drowsiness, ataxia, dizziness, headache, confusion, hallucinations, skin reactions, GI symptoms, enuresis. Potentially Fatal: Respiratory or CV depression, seizures.
Precautions
Warnings Intrathecal Abrupt discontinuation has resulted in high fever, altered mental status, exaggerated rebound spasticity, and muscle rigidity that in rare cases advances to rhabdomyolysis, multiple organ system failure and death. Give special attention to patients at apparent risk (eg, spinal cord injuries at T-6 or above, communication difficulties, history of withdrawal symptoms from oral or intrathecal baclofen). Renal Function Administer with caution. Dosage reduction may be necessary. Intrathecal use Only specially trained personnel should administer baclofen intrathecally because of potentially life-threatening CNS depression, CV collapse, or respiratory failure. Epilepsy and psychotic disorders Use with caution because of potential exacerbations. Fatalities Fatalities occurred in premarketing trials of intrathecal baclofen; baclofen's role in these deaths is unknown. Infection Patients should be infection-free before screening trial with baclofen intrathecal. Stroke Baclofen has not significantly benefited patients with stroke; these patients also have poor drug tolerance.
Special Precautions
Cerebrovascular disorders, epilepsy, severe psychotic disorders, confusional states, history of peptic ulcer, respiratory depression, DM, hepatic or renal impairment, elderly, pregnancy. Avoid sudden withdrawal.
Other Drug Interactions
Hypotensive effect may be increased with antihypertensives. Concomitant use with levodopa in Parkinson patients may result in confusion, agitation, hallucinations. Potentially Fatal: CNS depressants and alcohol may potentiate CNS effects.
Other Interactions
Information Not Available
Dosage
Oral Severe chronic spasticity Adult: Initially, 5 mg tid for 3 days increased to 10 mg tid for 3 days, then in similar increments and intervals until either 20 mg tid is reached or until desired effect is obtained. Max: 100 mg daily. Child: 0.75-2 mg/kg daily. May initiate with 2.5 mg 4 times daily, increased gradually every 3 days until desired effect is obtained. Maintenance: 6-10 yr: 30-60 mg daily; 2-6 yr: 20-30 mg daily; 12 mth-2 yr: 10-20 mg daily. Max: >10 yr: 2.5 mg/kg daily. Elderly: Initiate with lower doses. Renal impairment: Dose reduction may be required. Patients on chronic haemodialysis: 5 mg daily. Intrathecal Severe chronic spasticity Adult: Test dose: 25 or 50 mcg administered into the intrathecal space by barbotage over at least 1 minute; increase dose by 25 mcg not more often than every 24 hr until 100 mcg/dose to determine appropriate dose. Non-responders to a test dose of 100 mcg are not suitable for intrathecal treatment. For responders with response lasting >8-12 hr, the test dose that was used to produce the response can be given as a 24-hr infusion; if the test-dose response lasted ≤8-12 hr, then a dose equivalent to twice the test dose is given. Adjust daily dosage as required. Maintenance: 12 mcg-2 mg daily for spasticity of spinal origin; 22 mcg-1.4 mg daily for spasticity of cerebral origin. Child: 4-18 yr with spasticity of cerebral origin: Initially, 25 mcg over at least 1 minute via catheter or lumbar puncture, increase by 25 mcg every 24 hr to a max of 100 mcg to determine appropriate dose then dose-titration phase. Maintenance: <12 yr: 24 mcg-1.2 mg daily; >12 yr: 1.4 mg daily.
Food(before/after)
Should be taken with food
List of Contraindications
Baclofen and Pregnancy
Caution when used during pregnancy. 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.
Baclofen and Lactation
Information Not Available
Baclofen and Children
Information Not Available
Baclofen and Geriatic
Information Not Available
Baclofen and Other Contraindications
Hypersensitivity. Active peptic ulcer disease
Storage
Oral: Store below 25 ℃
Lab interference
Oral: Store below 25 ℃
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