Apo-Baclofen

Apo-Baclofen

baclofen

Manufacturer:

Apotex

Distributor:

Pharmaforte
Full Prescribing Info
Contents
Baclofen.
Description
Each tablet contains baclofen 20 mg.
Action
Pharmacotherapeutic Group: Muscle Relaxant, Antispastic Agent.
Pharmacology:
The precise mechanism of action of baclofen are not fully known. It inhibits both monosynaptic and polysynaptic reflexes at the spinal level, probably by hyperpolarization of afferent terminals, although actions at supraspinal sites may also occur and contribute to its clinical effect. Although baclofen is an analog of the putative inhibitory neurotransmitter γ-aminobutyric acid (GABA), there is no conclusive evidence that actions on GABA systems are involved in the production of its clinical effects.
Peak plasma concentrations of baclofen are achieved within 2 hours and the plasma half-life is 2-4 hours.
A controlled, two-way crossover bioavailability study was conducted in 20 volunteers to compare the drug serum levels produced by a single 20 mg oral dose of baclofen. The products compared were APO-BACLOFEN Tablets 20 mg, manufactured by Apotex Inc. and Lioresal Tablets 20 mg, manufactured by Geigy Pharmaceuticals. The following pharmacokinetic indices were found: See table.

Click on icon to see table/diagram/image
Indications/Uses
APO-BACLOFEN (baclofen) is useful for the alleviation of signs and symptoms of spasticity resulting from multiple sclerosis (MS).
Dosage/Direction for Use
The determination of optimal dosage of APO-BACLOFEN (baclofen) requires individual titration. Start therapy at a low dosage and increase gradually until optimum effect is achieved (usually between 40-80 mg daily).
The following dosage titration schedule is suggested: 5 mg t.i.d for 3 days; 10 mg t.i.d& for 3 days; 15 mg t.i.d for 3 days; 20 mg t.i.d for 3 days.
Thereafter additional increases may be necessary but the total daily dose should not exceed a maximum of 80 mg daily (20 mg q.i.d.).
The lowest dose compatible with an optimal response is recommended. If benefits are not evident after a reasonable trial period, patients should be slowly withdrawn from the drug (See Warnings).
Overdosage
Signs and Symptoms: Symptoms of overdosage are predominantly those of central nervous system depression and include drowsiness, impairment of consciousness, respiratory depression, coma, seizures, confusion, hallucinations, agitation, accomodation disorders, absent pupillary reflexes, muscular hypotonia, myoclonia, hyporeflexia or areflexia, hypotension, bradycardia, hypothermia, peripheral vasodilation, nausea, vomiting, diarrhea, increased salivation, elevated LDH, SGOT, AP and blood glucose values.
The signs and symptoms may be further aggravated by co-administration of a variety of other agents including alcohol, diazepam and tricyclic antidepressants.
Treatment: There is no specific antidote. The treatment is symptomatic. In the alert patient, empty the stomach promptly by induced emesis followed by gastric lavage. Adminster activated charcoal and if necessary, saline laxatives. In the obtunded patient, secure the airway with a cuffed endotracheal tube before beginning lavage (do not induce emesis).
Maintain adequate respiratory exchange; do not use respiratory stimulants. Muscular hypotonia may involve the respiratory muscles and require assisted respiration. Institute measures to support cardiovascular function. A high urinary output should be maintained since APO-BACLOFEN (baclofen) is excreted mainly by the kidneys. For this purpose, generous quantities of fluid should be administered, possibly together with a diuretic. Dialysis is indicated in severe poisoning associated with renal failure. In the event of convulsion, administer diazepam i.v. with caution.
Contraindications
Hypersensitiviy to APO-BACLOFEN (baclofen).
Warnings
Abrupt Drug Withdrawal: Following abrupt withdrawal of baclofen, visual and auditory hallucinations, convulsions (status epilepticus), dyskinesia, confusion, psychotic, manic or paranoid states, anxiety with tachycardia and sweating, insomnia and worsening of spasticity have occurred. Therefore, except for serious adverse reactions, the dose of APO-BACLOFEN (baclofen) should be reduced slowly when the drug is discontinued (over a period of approximately 1-2 weeks).
Impaired Renal Function: Because baclofen is primarily excreted unchange through the kidneys, it should be given with caution, and it may be necessary to reduce the dosage.
Stroke: Baclofen has not significantly benefited patients with stroke. These patients have also shown poor tolerableness to the drug.
Use in pregnancy: Safe use of baclofen during pregnancy or lactation has not been established. Baclofen crosses the placental barrier. High doses are associated with an increased incidence of abdominal hernias in the fetuses of rats and of ossification defects in those of rats and rabbits. Therefore, the drug should be administered to pregnant patients, or women of child-bearing potential only when, in the judgement of the physician, the potential benefits outweigh the possible hazards.
Special Precautions
Safe use of APO-BACLOFEN (baclofen) in children under age 12 has not been established and it is, therefore, not recommended for use in children.
Because of the possibility of sedation, patient should be cautioned regarding the operation of automobiles or dangerous machinery, and activities made hazardous by decreased alertness. Patients should also be cautioned that the central nervous system effects of baclofen may be additive to those of alcohol and other CNS depressants.
APO-BACLOFEN should be used with caution where spasticity is utilized to sustain upright posture and balance in locomotion, or whenever spasticity is utilized to obtain increased function.
Extreme caution should be exercised in patients with epilepsy or a history of convulsive disorders. In such patients, the clinical state and electroencephalogram should be monitored at regular intervals during therapy, as deterioration in seizure control and EEG has been reported occasionally in patients taking baclofen.
Caution should be used in treating patients with, or with a history of peptic ulceration, elderly patients with cerebrovascular disorders, and in patients with respiratory, hepatic or renal failure.
APO-BACLOFEN should be used with caution in patients with underlying bladder sphincter hypertonia, since acute retention of urine may occur.
Patients with psychiatric disorders such as psychosis, schizophrenia, or confusional states should be treated cautiously with APO-BACLOFEN and kept under close surveillance, since exacerbation of these conditions may occur with baclofen treatment.
The following laboratory tests have been found to be abnormal in a few patients receiving baclofen: SGOT, alkaline phosphatase and blood sugar (all elevated). Therefore, in patients with liver diseases or diabetes mellitus, appropriate laboratory tests should be performed periodically in order to ensure that no drug-induced changes in these underlying diseases have occurred.
The concomitant administration of baclofen and tricyclic antidepressants may potentiate the pharmacological effects of balcofen, resulting in pronounced muscular hypotonia.
The concurrent use of MAO inhibitor and baclofen may result in increased CNS-depressant effects, therefore, caution is advised and the dosage of one or both agents should be adjusted accordingly.
Since combined treatment with Parkinson's disease receiving treatment with baclofen and levodopa plus carbidopa, there have been several reports of mental confusion, hallucinations and agitation.
Isolated cases of increased blood glucose concentrations have reported with baclofen, dosage adjustments of antidiabetic agents (oral and insulin) may therefore be necessary with combine baclofen treatment.
Caution should be exercised with administering baclofen and magnesium sulfate (or other neuromuscular blocking agents), since a synergistic effect may theoretically occur.
Baclofen is excreted in human milk. As a general rule, nursing should not be undertaken while a patient is on a drug.
Use In Pregnancy & Lactation
Use in pregnancy: Safe use of baclofen during pregnancy or lactation has not been established. Baclofen crosses the placental barrier. High doses are associated with an increased incidence of abdominal hernias in the fetuses of rats and of ossification defects in those of rats and rabbits. Therefore, the drug should be administered to pregnant patients, or women of child-bearing potential only when, in the judgement of the physician, the potential benefits outweigh the possible hazards.
Baclofen is excreted in human milk. As a general rule, nursing should not be undertaken while a patient is on a drug.
Adverse Reactions
Adverse effects most frequently occur at the start of treatment, particularly if the dosage is increased to rapidly, if large doses are administered, and in the elderly patient. However, these effects are often transient and can be alleviated or eliminated by decreasing the dosage; they are seldom severe enough to warrant withdrawal of the medication. In elderly patients or those patients with cerebrovascular disorder or a history of psychiatric illness, more serious adverse reactions may occur, such as hallucinations and confusion.
The most common adverse reactions associated with baclofen are transient drowsiness, daytime sedation, dizziness, weakness and fatigue. Others reported: Central Nervous System: Headache (<10%), insomnia (<10%), and rarely, euphoria, excitement, depression, confusion, hallucinations, paresthesia, nightmares, muscle pain, tinnitus, slurred speech, coordination disorder, strabismus, miosis, mydriasis, diplopia, dysarthria, epileptic seizures, respiratory depression.
Cardiovascular: Hypotension (<10%), rare instances of dyspnea, palpitation, chest pain, syncope.
Gastrointestinal: Nausea (approx. 10%), constipation (<10%), and rarely dry mouth, anorexia, taste disorder, abdominal pain, vomiting, diarrhea and positive test for occult blood in stool.
Genitourinary: Urinary frequency (<10%), and rarely enuresis, urinary retention, dysuria, impotence, inability to ejaculate, nocturia, hematuria.
Other: Instances of rash, pruritus, ankle edema, excessive perspiration, weight gain, nasal congestion, visual disturbances, hepatic function disorders, and paradoxical increase in spasticity.
Muscular hypotonia of a degree sufficient to make walking or movement difficult may occur, but is usually relieved by readjusting the dosage. For this purpose the daytime may be reduce and the evening dose increased.
Some of the CNS and genitourinary symptoms reported may be related to the underlying disease rather than to drug therapy.
Storage
Store in a cool, dry place. Protect from light.
MIMS Class
ATC Classification
M03BX01 - baclofen ; Belongs to the class of other centrally-acting muscle relaxants.
Presentation/Packing
Tab 20 mg x 100's.
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