This dosage information may not include all the information needed to use Vigabatrin safely and effectively. See additional information for Vigabatrin.
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Usual Adult Dose for:
Usual Pediatric Dose for:
Additional dosage information:
Usual Adult Dose for Seizure Prophylaxis
Initial dose: 1 g/day (administered as one 500 mg tablet orally twice daily) with or without food
The total daily dose may be increased in 500 mg increments at weekly intervals depending on response.
Recommended dose: 3 g/day (1.5 g twice daily)
A 6 g/day dose has not been shown to confer additional benefit compared to the 3 g/day dose and is associated with an increased incidence of adverse events.
Usual Pediatric Dose for Epilepsy
1 Month to 2 Years of Age:
Initial dose: 50 mg/kg/day of vigabatrin oral solution given in two divided doses with or without food. The dose may be titrated by 25 to 50 mg/kg/day increments every 3 days up to a maximum of 150 mg/kg/day.
The entire contents of the appropriate number of packets (500 mg/packet) of powder should be emptied into an empty cup, and should be dissolved in 10 mL of cold or room temperature water per packet using the 10 mL oral syringe supplied with the medication. The concentration of the final solution is 50 mg/mL.
Each individual dose should be prepared immediately before use and administered cold or at room temperature.
Renal Dose Adjustments
In patients with mild renal impairment (CrCl 51 to 80 mL/min), the dose should be decreased by 25%. In patients with moderate renal impairment (CrCl 31 to 50 mL/min), the dose should be decreased by 50%. In patients with severe renal impairment (CrCl 11 to 30 mL/min), the dose should be decreased by 75%.
Liver Dose Adjustments
Data not available
As with all antiepileptic drugs, vigabatrin should be withdrawn gradually. In controlled clinical studies in adults with CPS, vigabatrin was tapered by decreasing the daily dose 1 g/day on a weekly basis until discontinued.
Oral administration of a single dose of 1.5 g of vigabatrin to elderly patients (over 65 years of age) with reduced creatinine clearance (less than 50 mL/min) has been associated with moderate to severe sedation and confusion in 4 of 5 patients, lasting for up to 5 days. The renal clearance of vigabatrin was 36% lower in healthy elderly subjects (over 65 years of age) than in young healthy males. Adjustment of dose or frequency of administration should be considered. Such patients may respond to a lower maintenance dose. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.
Physicians should review and discuss the medication guide with the caregiver(s) prior to preparation and administration of vigabatrin oral solution. Physicians should confirm that caregiver(s) understand how to reconstitute vigabatrin oral solution and to administer the correct dose to their infants.
Clinical studies of vigabatrin did not include sufficient numbers of patients aged 65 and over to determine whether they responded differently from younger patients. Vigabatrin is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.
The effect of dialysis on vigabatrin clearance has not been adequately studied. In isolated case reports in renal failure patients receiving therapeutic doses of vigabatrin, hemodialysis reduced vigabatrin plasma concentrations by 40% to 60%.
The US FDA requires a Risk Evaluation and Mitigation Strategy (REMS) for vigabatrin. This includes a medication guide, communication plan, elements to assure safe use, an implementation system, and a timetable for submission of assessments. Additional information is available at www.fda.gov/Drugs/DrugSafety/postmarketDrugSafetyInformationforPatientsandProviders/ucm111350.htm.
The lowest dose and shortest exposure to vigabatrin should be used that is consistent with clinical objectives. Because of the risk of permanent vision loss vigabatrin is available only through a special restricted distribution program called SHARE, by calling 1-888-45-SHARE. Only prescribers and pharmacies registered with SHARE may prescribe and distribute vigabatrin. In addition, vigabatrin may be dispensed only to patients who are enrolled in and meet all conditions of SHARE.