Fenobac

Light pink circular biconvex (S) tablet, one score on one side.
Baclofen is an effective muscle relaxant and antispastic agent with a spinal site of action. Baclofen is structurally similar to the inhibitory neurotransmitter gamma-amino-butyric acid, though its actions are different. It is stereospecifically to GABA_B receptors. It is thought that activation of the GABA_B receptors on presynaptic terminal reduces evoked transmitter release, perhaps through reduced presynaptic Ca²⁺ influx. Baclofen can inhibit the function of inward calcium currents in some cells. The drug rapidly absorbed after oral administration and is widely distributed throughout the body.
Each tablet contains: Baclofen 10 mg.

Pharmacotherapeutic group: Antispastic with spinal site attack.
Pharmacology: Pharmacodynamics: Baclofen is an antispastic agent acting at the spinal level. A gamma-aminobutyric acid (GABA) derivative, baclofen is chemically unrelated to other antispastic agents.
Baclofen depresses monosynaptic and polysynaptic reflex transmission, probably by stimulating the GABA_B-receptors, this stimulation in turn inhibiting the release of the excitatory amino acids glutamate and aspartate. Neuromuscular transmission is unaffected by baclofen.
The major benefits of baclofen stem from its ability to reduce painful flexor spasms and spontaneous clonus thereby facilitating the mobility of the patient, increasing his independence and helping rehabilitation.
Baclofen also exerts an antinociceptive effect. General well being is often improved and sedation is less often a problem than with centrally acting drugs.
Baclofen stimulates gastric acid secretion.
Pharmacokinetics: Absorption: Baclofen is rapidly and completely absorbed from the gastrointestinal tract. No significant difference between the liquid and tablet formulations is observed in respect of Tmax, Cmax and bioavailability. Following oral administration of single doses (10-30 mg) peak plasma concentrations are recorded after 0.5 to 1.5 hours and areas under the serum concentration curves are proportional to the dose.
Distribution: The volume of distribution of baclofen is 0.7 L/kg. The protein binding rate is approximately 30% and is constant in the concentration range of 10 nanogram/mL to 300 microgram/mL. In cerebrospinal fluid active substance concentrations are approximately 8.5 times lower than in the plasma.
Biotransformation: Baclofen is metabolised to only a minor extent. Deamination yields the main metabolite, β-(p-chlorophenyl)-4-hydroxybutyric acid, which is pharmacologically inactive.
Elimination/excretion: The plasma elimination half-life of baclofen averages 3 to 4 hours.
Baclofen is eliminated largely in unchanged form. Within 72 hours, approximately 75% of the dose is excreted via the kidneys with about 5% of this amount as metabolites.
Special populations: Elderly patients (aged 65 years or above): The pharmacokinetics of baclofen in elderly patients are virtually the same as in patients below 65 years of age. Following a single oral dose, elderly patients have slower elimination but a similar systemic exposure of baclofen compared to adults below 65 years of age. Extrapolation of these results to multi-dose treatment suggests no significant pharmacokinetic difference between patients below 65 years of age and elderly patients.
Paediatric patients: Following oral administration of 2.5 mg baclofen tablet in children (aged 2 to 12 years), Cmax of 62.8±28.7 nanogram/mL, and Tmax in the range of 0.95-2 h have been reported. Mean plasma clearance (CI) of 315.9 mL/h/kg; volume of distribution (Vd) of 2.58 L/kg; and half-life (T1/2) of 5.10 h have been reported.
Hepatic impairment: No pharmacokinetic data are available in patients with hepatic impairment after administration of baclofen. However, as the liver does not play a significant role in the disposition of baclofen, it is unlikely that baclofen pharmacokinetics would be altered to a clinically significant level in patients with hepatic impairment.
Renal impairment: No controlled clinical pharmacokinetic study is available in patients with renal impairment after administration of baclofen. Baclofen is predominantly eliminated unchanged in urine. Sparse plasma concentration data collected only in female patients under chronic hemodialysis or compensated renal failure indicate significantly decreased clearance and increased half-life of baclofen in these patients. Dosage adjustment of baclofen based on its systemic levels should be considered in renal impairment patients, and prompt hemodialysis is an effective means of reversing excess baclofen in systemic circulation.

The control of spasticity caused by multiple sclerosis and spinal cord lesions.
The control of spasticity in children caused by cerebral palsy.
The adjunctive management of neurogenic bladder.
The management of refractory trigeminal neuralgia.
Not recommended in Parkinson's disease or spasticity arising from strokes, cerebral palsy or rheumatoid disorder.

Take note optimum dosage generally ranges from 30 mg to 75 mg daily, although occasionally in hospitalized patients daily doses up to 100 mg may be necessary.
The dose should be titrated to gain maximum benefit and minimize adverse reactions.
Tablets should be taken with food or mild drink to reduce gastrointestinal intolerance.
Baclofen should be withdrawn gradually if cessation of therapy is indicated.
Adults: The usual starting dose of Baclofen for adults is 5 mg given three times daily. Based on the response, the dose can be increased gradually every three days by 5 mg to a maximum of 80 mg/day in several doses. If benefits are not evident after a 6 to 8 weeks trial period, patients should be slowly withdrawn from the drug.
Children: In children aged 12-24 months, the recommended daily dose is 10-20 mg, and in children aged 2-10 years, 20-60 mg per day (from starting dose 0.3-0.75 mg/kg body weight per day up-to 2 mg/kg body weight per day).
Elderly: Dosage should be cautiously administered and the patient kept under appropriate surveillance. Toxicity due to Baclofen may be mistaken for uremic encephalopathy.
Impaired Renal Function: Baclofen should be used with caution. Lower doses (approximately 5 mg per day) should be used for patients with impaired renal function or those undergoing chronic haemodialysis.
Or as prescribed by the physician.

Symptoms: Prominent features are signs of central nervous depression: somnolence, depressed level of consciousness, coma, respiratory depression. Also liable to occur are: confusion, hallucination, agitation, convulsion, abnormal electroencephalogram (burst suppression pattern and triphasic waves), accommodation disorder, impaired pupillary reflex, generalised muscular hypotonia, myoclonus, hyporeflexia or areflexia, peripheral vasodilatation, hypotension or hypertension, bradycardia, tachycardia or cardiac arrhythmia, hypothermia, nausea, vomiting, diarrhoea, salivary hypersecretion, increased hepatic enzymes and rhabdomyolysis. Patients with renal impairment can develop signs of overdose even on low doses of oral baclofen.
A deterioration in the condition may occur if various substances or drugs acting on the central nervous system (e.g. alcohol, diazepam, tricyclic antidepressants) have been taken at the same time.
Treatment: No specific antidote is known.
Supportive measures and symptomatic treatment should be given for complications such as hypotension, hypertension, convulsions, gastrointestinal disorders and respiratory or cardiovascular depression.
Since the drug is excreted chiefly via the kidneys, generous quantities of fluid should be given, possibly together with a diuretic. Haemodialysis (sometimes unscheduled) may be useful in severe poisoning associated with renal failure.

Baclofen is contraindicated in epilepsy, spasticity of functional significance, rheumatic muscle spasm and patients who are hypersensitive to any component of this product.

Slowly reduce dose when drug is discontinued. Hallucinations and seizures have occurred on abrupt withdrawal of Baclofen.

Baclofen should be used with caution in patients who use their spasticity to maintain posture or to increase function. In patient with epilepsy, the clinical state and electroencephalogram should be monitored at regular intervals, since deterioration is seizure control and EEG have been reported occasionally in patient taking Baclofen. Because of possibility of sedation, patients should be cautioned regarding the operation of automobiles or other dangerous machinery and activities made hazardous by decreased alertness. Patient should be cautioned that CNS depressant effects of Baclofen may be additive to those of alcohol and other CNS depressants.

Pregnancy Category C. There are no adequate and well-controlled studies in pregnant women. Baclofen should be used during pregnancy only if the potential benefit justifies the potential risk of the fetus. In mothers treated with oral Baclofen in therapeutic doses, the active substance passes into the breast milk. Therefore, administration to nursing mothers is not recommended.

Common adverse reactions include sedation, lethargy, vertigo, headache, nausea and diarrhea. Other infrequent side-effects are muscular hypotonia, urinary disturbances, confusion, speech disturbances, ataxia, hallucination, nightmares, euphoria, insomnia, depression, anxiety, agitation, tremor, nystagmus, paresthesias, seizures, myalgia, fever, respiratory or cardiovascular depression, hypotension, dry mouth, gastrointestinal disorder, sexual dysfunction, visual disorder, rash, pruritus, urticaria, hyperhidrosis, angioedema, rarely taste alterations, blood sugar changes and paradoxical increase in spasticity. Some of the CNS and genitourinary symptoms may be related to the underlying diseases rather than to drug therapy.

Antihypertensives: Baclofen has an occasional hypotensive effect and should be used with care in conjunction with antihypertensive agents.
CNS depressant: The CNS depressant effect of Baclofen may be additive to those of CNS depressants.
Lithium: Baclofen may produce severe aggravation of hyperkinetic symptoms in patients receiving lithium.

Store at temperatures not exceeding 30°C.

Muscle Relaxants

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

Rx