Gabix

Gabix

gabapentin

Manufacturer:

Getz Pharma

Distributor:

Getz Pharma
Full Prescribing Info
Contents
Gabapentin.
Description
Gabix is a new antiepileptic drug that is structurally similar to the neurotransmitter gamma-aminobutyric acid (GABA) and the endogenous amino acid L-leucine. Chemically, gabapentin is 1-(aminomethyl)-cyclohexaneacetic acid. Its molecular formula is C9H17NO2.
Action
Pharmacology: Mechanism of Action: Gabapentin has proven affinity for special site in brain tissues eg, neocortex and hippocampus. Though exact mechanism of its central nervous system (CNS) depressant and anticonvulsant activity is not fully understood, it is thought to be activated through peptide binding sites (receptor). It also has analgesic activity.
Pharmacokinetics: Absorption: Gabapentin is absorbed from the gastrointestinal tract (GIT) by means of saturable mechanism. Gabapentin bioavailability is not dose proportional ie, as dose is increased, bioavailability is decreased. Absolute bioavailability of 300-mg oral dose is approximately 60%. At doses of 300 and 400 mg, gabapentin bioavailability was unchanged following multiple dose administration. Food has no effect on the rate and extent of absorption.
Distribution: Gabapentin circulates largely unbound (<3%) to plasma proteins. It is distributed into breast milk and has a volume of distribution equal to 57.7 L.
Metabolism and Elimination: Gabapentin is not appreciably metabolized and is eliminated from the systemic circulation by renal excretion as unchanged drug. Elimination t½ ranges from 5-7 hrs and is unaltered by dose or following multiple dosing. Gabapentin elimination rate constant, plasma and renal clearance are directly proportional to creatinine clearance (CrCl).
Special Populations: Renal Insufficiency: The mean gabapentin t½ ranged from about 6.5 hrs (patients with CrCl >60 mL/min) to 52 hrs (CrCl <30 mL/min) and gabapentin renal clearance ranged from 90 mL/min (CrCl >60 mL/min) to about 10 mL/min (CrCl <30 mL/min). Gabapentin dosage should be adjusted in patients with compromised renal function.
Patients on Hemodialysis: In anuric patients, the elimination t½ of gabapentin on a nondialysis day was about 132 hrs; during dialysis the apparent t½ was reduced to 3.8 hrs. Thus, hemodialysis has a significant effect on gabapentin elimination in anuric patients. Gabapentin dosage should be adjusted in patients undergoing hemodialysis.
Elderly: The apparent oral clearance (CL/F) of gabapentin decreased as age increased, from about 225 mL/min in those <30 years to about 125 mL/min in those >70 years. Reduction of gabapentin dose may be required in patients who have age-related compromised renal function.
Drug-Drug Interactions: Naproxen: Co-administration of naproxen sodium (250 mg) with gabapentin (125 mg) appears to increase the amount of gabapentin absorbed by 12-15%. These doses are lower than the therapeutic doses for both drugs. The magnitude of interaction within the recommended dose is not known.
Hydrocodone: Co-administration of gabapentin decreases hydrocodone Cmax and area under the curve (AUC) values in a dose-dependent manner relative to administration of hydrocodone alone. Hydrocodone increases gabapentin AUC values by 14%.
Morphine: When morphine 60 mg is administered 2 hrs prior to gabapentin 600 mg, the mean gabapentin AUC increased by 44% compared to gabapentin administered without morphine.
Indications/Uses
Epilepsy: Adjunctive therapy in the treatment of partial seizures with or without secondary generalization in adults and children ≥6 years.
Monotherapy in the treatment of partial seizures with or without secondary generalization in adults and adolescents ≥12 years.
Neuropathic Pain: Postherpetic neuralgia (PHN), peripheral diabetic neuropathies and trigeminal neuralgia in adults.
Dosage/Direction for Use
Gabix is given in titrations that lead to an effective dose. Treatment progresses rapidly and can be accomplished over a few days. The total dose should be divided into 3 doses given at intervals not exceeding 12 hrs.
In patients with poor general health ie, low body weight, after organ transplantation, the dose should be titrated more slowly, either by using smaller dosage strengths or longer intervals between dosage increases.
Epilepsy: Epilepsy typically requires long-term therapy. Dosage is determined by the treating physician according to individual tolerance and efficacy.
Adults and Children >12 years: Effective Dosing Range: 900-3600 mg/day. Therapy may be initiated by titrating the dose (described as follows) or by administrating 300 mg 3 times a day on day 1.
Dose Titration: Day 1: 300 mg once a day. Day 2: 300 mg 2 times a day. Day 3: 300 mg 3 times a day.
Thereafter, based on individual patient response and tolerability, the dose can be further increased in increments of 300 mg/day every 2-3 days up to a maximum dose of 3600 mg/day.
Slower titration of gabapentin dosage may be appropriate for individual patients. The minimum time to reach a dose of 1800 mg/day is 1 week, to reach 2400 mg/day is a total of 2 weeks and to reach 3600 mg/day is a total of 3 weeks. The total daily dose should be divided in 3 single doses, the maximum time interval between the doses should not exceed 12 hrs to prevent breakthrough convulsions.
Children ≥6 years: Starting Dose: 10-15 mg/kg/day. The effective dose is reached by upward titration over a period of approximately 3 days. The effective dose of gabapentin in children ≥6 years is 25-35 mg/kg/day. Dosages up to 50 mg/kg/day have been well-tolerated. The total daily dose should be divided in 3 single doses, the maximum time interval between doses should not exceed 12 hrs. Gabapentin may be used in combination with other antiepileptic medicinal products without concern for alteration of the plasma concentrations of gabapentin or serum concentrations of other antiepileptic medicinal products.
Neuropathic Pain: The therapy may be initiated by titrating the dose as follows: Day 1: 300 mg once a day. Day 2: 300 mg 2 times a day. Day 3: 300 mg 3 times a day.
Alternatively, the starting dose is 900 mg/day given as 3 equally divided doses. Thereafter, based on individual patient response and tolerability, the dose can be further increased in increments of 300 mg/day every 2-3 days up to a maximum dose of 3600 mg/day.
Slower titration of gabapentin dosage may be appropriate for individual patients. The minimum time to reach a dose of 1800 mg/day is 1 week, to reach 2400 mg/day is a total of 2 weeks and to reach 3600 mg/day is a total of 3 weeks.
Patients with Renal Impairment: A dosage adjustment is recommended in renally impaired patients and/or those undergoing hemodialysis.
Creatinine Clearance ≥80 mL/min: Total Daily Dosea: 900-3600 mg/day. 50-79 mL/min: 600-1800 mg/day. 30-49 mL/min: 300-900 mg/day. 15-29 mL/min: 150b-600 mg/day. <15c mL/min: 150b-300 mg/day.
aTotal daily dose should be administered as a 3 times a day regimen. Doses used to treat patients with normal renal function (CrCl >80 mL/min) range from 900-3600 mg/day. Reduced dosages are for patients with renal impairment (CrCl <79 mL/min).
bTo be administered as 300 mg on every other day.
cFor patients with CrCl <15 mL/min, the daily dose should be reduced in proportion to CrCl (eg, patients with CrCl of 7.5 mL/min should receive ½ of the daily dose that patients with CrCl of 15 mL/min receive).
Anuric Patients Undergoing Hemodialysis Who Have Never Received Gabapentin: 300-400 mg loading dose then 200-300 mg of Gabix following each 4 hrs of hemodialysis. On dialysis-free days, there should be no treatment with gabapentin.
Renally Impaired Patients Undergoing Hemodialysis: Maintenance dose of gabapentin should be based on the dosing recommendations mentioned previously. In addition to the maintenance dose, an additional dose of 200-300 mg following each 4-hr hemodialysis treatment is recommended.
Discontinuation of Gabix: If gabapentin has to be discontinued, it is recommended that this should be done gradually over a minimum of 1 week independent of the indication.
Administration: Gabix may be given orally with or without food and should be swallowed whole with sufficient fluid intake (eg, a glass of water).
Overdosage
Acute life-threatening toxicity has not been observed with gabapentin overdose of up to 49 g. Symptoms of the overdosage included dizziness, double vision, slurred speech, drowsiness, lethargy and mild diarrhea. Reduced absorption of gabapentin at higher doses may limit drug absorption at the time of overdosing and, hence, minimize toxicity overdose.
Overdose of gabapentin, particularly in combination with other CNS depressant medications may result in coma.
In patients with severe renal impairment, hemodialysis may be indicated.
Contraindications
Patients with known hypersensitivity to gabapentin or any of the components of Gabix.
Special Precautions
Patients should be monitored for signs of suicidal ideation and behaviors and appropriate treatment should be considered. Patients (and caregivers of patients) should be advised to seek medical advice and should watch for signs of suicidal ideation or behavior.
If a patient develops acute pancreatitis under treatment with gabapentin, discontinuation of gabapentin should be considered.
Abrupt withdrawal of anticonvulsant agents in epileptic patients may precipitate status epilepticus.
As with other antiepileptic medicinal products, an increase in seizure frequency or the onset of new types of seizures with gabapentin.
Gabapentin should not be considered a treatment of absence seizures. It may exacerbate these seizures in some patients. Consequently, gabapentin should be used with caution in patients who have mixed seizure disorders that include absence seizures.
Effects on the Ability to Drive or Operate Machinery: Patients should be advised neither to drive a car nor to operate complex machinery until they have gained sufficient experience on gabapentin.
Use in pregnancy: There are no adequate and well-controlled studies in pregnant women. Gabapentin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Use in lactation: Gabapentin is excreted into breast milk following oral administration. The effect on the nursing infant is unknown. Therefore, gabapentin should be used in nursing women only if the potential benefits clearly outweigh the risks.
Use In Pregnancy & Lactation
Use in pregnancy: There are no adequate and well-controlled studies in pregnant women. Gabapentin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Use in lactation: Gabapentin is excreted into breast milk following oral administration. The effect on the nursing infant is unknown. Therefore, gabapentin should be used in nursing women only if the potential benefits clearly outweigh the risks.
Adverse Reactions
The following adverse reactions have been reported:
Central Nervous System: Somnolence, dizziness, ataxia, abnormal thinking and coordination, amnesia, depression, dysarthria, nervousness, twitching, tremor, hyperkinesias, hostility, emotional lability in children 3-12 years.
Dermatologic: Pruritus.
Metabolic: Weight gain.
Gastrointestinal Tract: Nausea, vomiting, dyspepsia, appetite stimulation, constipation, xerostomia.
Hematologic: Increased or decreased white blood cell (WBC) count.
Ophthalmologic: Nystagmus, diplopia, blurred vision.
Musculoskeletal: Back pain, myalgia.
Others: Dry throat, fatigue, viral infection, fever, peripheral edema, dental abnormalities, impotence.
Drug Interactions
Phenytoin, Valproic Acid, Carbamazepine, Phenobarbitone and Felbamate: There is no interaction during the concomitant administration of gabapentin with these drugs. Gabapentin steady-state pharmacokinetics is similar for healthy subjects and patients with epilepsy receiving antiepileptic agents.
Morphine: Patients who require concomitant treatment with morphine may experience increases in gabapentin concentrations. Patients should be carefully observed for signs of CNS depression eg, somnolence and the dose of gabapentin or morphine should be reduced appropriately.
Antacid: Gabapentin's bioavailability was reduced by up to 24% when co-administered at the same time with an aluminum- and magnesium-containing antacid. It is recommended that gabapentin be taken about 2 hrs following any such antacid administration.
Cimetidine: Cimetidine may increase serum concentration of gabapentin by decreasing its clearance by 14%.
Oral Contraceptives: Co-administration of gabapentin with oral contraceptives including norethindron, norethisterone and/or ethinyl estradiol does not influence the steady-state pharmacokinetics of either component.
Storage
Store at temperatures not exceeding 30°C. Protect from sunlight and moisture.
Shelf-Life: 24 months.
MIMS Class
ATC Classification
N03AX12 - gabapentin ; Belongs to the class of other antiepileptics.
Presentation/Packing
Cap 100 mg x 10's. 300 mg x 10's.
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