Trilaxant

Pharmacology: Pharmacokinetics: Baclofen is rapidly and almost completely absorbed from the gastrointestinal tract following an oral dose. Peak plasma concentrations occur about 0.5-3 hrs after ingestion, but the rate and extent of absorption vary between patients and may vary inversely with the dose. After oral doses, some baclofen crosses the blood-brain barrier with a concentration in the cerebrospinal fluid (CSF) of about 12% of those in the plasma. Approximately 30% of baclofen is bound to plasma proteins. About 70-80% of the dose is excreted in the urine mainly as unchanged drug while about 15% is metabolized in the liver. The elimination t_½ of baclofen is about 3-4 hrs in plasma and about 1-5 hrs in the CSF. Baclofen crosses the placenta and is distributed into breast milk.

Symptomatic relief of severe chronic spasticity associated with a variety of conditions; reduction of muscle spasm and pain especially in spinal cord lesions in conditions eg, multiple sclerosis or paraplegia; spasticity of cerebral origin.

The initial dose is 5 mg thrice daily for 3 days, increased to 10 mg thrice daily for 3 days, then in similar increments and intervals until either a dose of 20 mg thrice daily is reached or until the desired therapeutic effect is obtained. Higher doses have been used.
Doses >80-100 mg daily are not generally recommended, although doses of up to 150 mg daily have been given to carefully supervised patients.
Children >10 years: A maximum daily dosage of 2.5 mg/kg may be given. It is usual to start with a low dose of 2.5 mg given 4 times daily, increased cautiously about every 3 days until the desired therapeutic effect is obtained. Recommended Daily Maintenance Doses: 6-10 years: 30-60 mg; 2-6 years: 20-30 mg; 12 months to 2 years: 10-20 mg.
Elderly: Lower initial doses should be given, although final maintenance doses maybe in the same range as younger adults.
Renal Impairment/Patients Undergoing Chronic Hemodialysis: Doses of baclofen should be reduced to 5 mg daily as suggested. If no benefit is apparent within 6 weeks of achieving the maximum dosage, therapy should probably be gradually withdrawn.
Administration: Baclofen is given by mouth in divided doses, preferably with or after food or milk.

Symptoms: Overdosage may lead to muscular hypotonia, drowsiness, respiratory depression, coma and convulsions.
Treatment: Treatment of overdosage is symptomatic. Consideration should be given to gastric lavage and/or the use of activated charcoal in patients who have ingested >100 mg within 1 hr of presentation; activated charcoal is recommended in children who have taken >5 mg/kg or 100 mg within the last hr. Observation should continue for at least 6 hrs after ingestion.
Atropine sulfate 600 mcg IV was used to treat a patient who had ingested 420 mg of baclofen and had failed to improve after gastric lavage and induced diuresis.

Baclofen stimulates gastric acid secretion and should be used with caution in patients with a history of peptic ulcer and avoided in those with active peptic ulcer disease. It should also be used with caution in patients with severe psychiatric disorders or epilepsy, or convulsion disorders since these disorders may be exacerbated by baclofen. Liver function should be monitored in patients with liver disease; patients with renal impairment need a reduced dose. Baclofen should be used with caution in patients with respiratory impairment.
Observations of increased blood sugar concentrations suggest caution in patients with diabetes mellitus.
Care is also required in the elderly, in whom adverse effects maybe more common, and in patients with cerebrovascular disease (who tolerate baclofen poorly).
Baclofen should be used with caution in patients who use their spasticity to maintain posture or to increase function.
Urine retention may be exacerbated in patients with hypertonic bladder sphincters.
Abrupt withdrawal of baclofen may result in a withdrawal syndrome and exacerbation of spasticity; dosage should be reduced gradually over at least 1-2 weeks or longer if symptoms occur.
Effects on the Ability to Drive or Operate Machinery: Baclofen may cause drowsiness. Patients affected should not drive or operate machinery.

The most common side effects include drowsiness, nausea, dizziness, lassitude, lightheadedness, confusion, fatigue, muscular pain and weakness, and hypotension. Other side effects include euphoria, hallucinations, depression, headache, tinnitus, convulsions, paresthesias, slurred speech, dry mouth, taste alterations, vomiting, diarrhea or constipation, ataxia, nystagmus, tremors, insomnia, visual disturbances, skin rashes, pruritus, increased sweating, urinary disturbances, respiratory or cardiovascular depression, blood sugar changes, alterations in liver function values and a paradoxical increase in spasticity.

Alcohol and other CNS depressants may exacerbate the CNS effects of baclofen and should be avoided; severe aggravation of hyperkinetic symptoms may possibly occur in patients taking lithium.
There may be increased weakness if baclofen is given to patients taking a tricyclic antidepressant and there may be an increased hypotensive effect if it is given to patients receiving antihypertensive therapy.
Ibuprofen and other drugs that produce renal insufficiency may reduce baclofen excretion leading to toxicity.

Store at temperatures not exceeding 25°C.

Muscle Relaxants

M03BX01 - baclofen ; Belongs to the class of other centrally-acting muscle relaxants.

Rx