Revision Year: 2024
VIGAFYDE is indicated as monotherapy for the treatment of infantile spasms in pediatric patients 1 month to 2 years of age for whom the potential benefits outweigh the potential risk of vision loss [see Warnings and Precautions (5.1)].
VIGAFYDE is a solution of 100 mg/mL of vigabatrin intended for oral use only. VIGAFYDE is a concentrated solution as compared to other vigabatrin products. Verify strength and the dose of the product prior to prescribing, dispensing, and administering [see Dosage and Administration (2.3)]. VIGAFYDE does not require additional reconstitution or dilution prior to administration.
Use the lowest dosage and shortest exposure to VIGAFYDE consistent with clinical objectives [see Warnings and Precautions (5.1)].
The VIGAFYDE dosing regimen depends on weight.
Monitoring of VIGAFYDE plasma concentrations to optimize therapy is not helpful.
VIGAFYDE is given orally with or without food.
A calibrated measuring device is recommended to measure and deliver the prescribed dose accurately. A household teaspoon or tablespoon is not an adequate measuring device.
If a decision is made to discontinue VIGAFYDE, the dose should be gradually reduced [see Dosage and Administration (2.2) and Warnings and Precautions (5.5)].
The initial daily dosing is 50 mg/kg/day given in two divided doses (25 mg/kg twice daily); subsequent dosing can be titrated by 25 mg/kg/day to 50 mg/kg/day increments every 3 days, up to a maximum of 150 mg/kg/day given in 2 divided doses (75 mg/kg twice daily) [see Use in Specific Populations (8.4)].
Table 1 provides the volume of the 50 mg/mL dosing solution that should be administered as individual doses in infants of various weights.
Table 1. Dosing of VIGAFYDE for Infantile Spasms:
| Weight [kg] | Starting Dose 50 mg/kg/day | Maximum Dose 150 mg/kg/day |
|---|---|---|
| 3 | 75 mg (0.75 mL) twice daily | 225 mg (2.25 mL) twice daily |
| 4 | 100 mg (1 mL) twice daily | 300 mg (3 mL) twice daily |
| 5 | 125 mg (1.25 mL) twice daily | 375 mg (3.75 mL) twice daily |
| 6 | 150 mg (1.5 mL) twice daily | 450 mg (4.5 mL) twice daily |
| 7 | 175 mg (1.75 mL) twice daily | 525 mg (5.25 mL) twice daily |
| 8 | 200 mg (2 mL) twice daily | 600 mg (6 mL) twice daily |
| 9 | 225 mg (2.25 mL) twice daily | 675 mg (6.75 mL) twice daily |
| 10 | 250 mg (2.5 mL) twice daily | 750 mg (7.5 mL) twice daily |
| 11 | 275 mg (2.75 mL) twice daily | 825 (8.25 mL) twice daily |
| 12 | 300 mg (3 mL) twice daily | 900 (9 mL) twice daily |
| 13 | 325 mg (3.25 mL) twice daily | 975 mg (9.75 mL) twice daily |
| 14 | 350 mg (3.5 mL) twice daily | 1050 mg (10.5 mL) twice daily |
| 15 | 375 mg (3.75 mL) twice daily | 1125 mg (11.25 mL) twice daily |
| 16 | 400 mg (4 mL) twice daily | 1200 mg (12 mL) twice daily |
In patients with infantile spasms, VIGAFYDE should be withdrawn if a substantial clinical benefit is not observed within 2 to 4 weeks. If, in the clinical judgment of the prescriber, evidence of treatment failure becomes obvious earlier than 2 to 4 weeks, treatment should be discontinued at that time [see Warnings and Precautions (5.1)].
If switching between other vigabatrin products and VIGAFYDE, ensure the correct volume for the correct dosage is prescribed, dispensed, and administered. As compared to other vigabatrin products, VIGAFYDE is a concentrated solution that requires a smaller volume than other vigabatrin products to obtain the same dosage (i.e., VIGAFYDE is 100 mg/mL and currently available vigabatrin for oral solution products have a final concentration of 50 mg/mL).
Avoid abrupt withdrawal [see Warnings and Precautions (5.5)]. In a controlled clinical study in patients with infantile spasms, vigabatrin was tapered by decreasing the daily dosage at a rate of 25-50 mg/kg every 3-4 days.
Confirmed and/or suspected vigabatrin overdoses have been reported during clinical trials and in post marketing surveillance. No vigabatrin overdoses resulted in death. When reported, the vigabatrin dose ingested ranged from 3 g to 90 g, but most were between 7.5 g and 30 g. Nearly half the cases involved multiple drug ingestions including carbamazepine, barbiturates, benzodiazepines, lamotrigine, valproic acid, acetaminophen, and/or chlorpheniramine.
Coma, unconsciousness, and/or drowsiness were described in the majority of cases of vigabatrin overdose. Other less commonly reported symptoms included vertigo, psychosis, apnea or respiratory depression, bradycardia, agitation, irritability, confusion, headache, hypotension, abnormal behavior, increased seizure activity, status epilepticus, and speech disorder. These symptoms resolved with supportive care.
There is no specific antidote for VIGAFYDE overdose. Standard measures to remove unabsorbed drug should be used, including elimination by emesis or gastric lavage. Supportive measures should be employed, including monitoring of vital signs and observation of the clinical status of the patient.
In an in vitro study, activated charcoal did not significantly adsorb vigabatrin.
The effectiveness of hemodialysis in the treatment of VIGAFYDE overdose is unknown. In isolated case reports in renal failure patients receiving therapeutic doses of vigabatrin, hemodialysis reduced vigabatrin plasma concentrations by 40% to 60%.
Store unopened bottles at room temperature between 20°C to 25°C (68°F to 77°F) with excursions permitted to 15°C to 30°C (59°F to 86°F) [See USP Controlled Room Temperature].
Once opened, store bottle in a refrigerator or at room temperature between 2°C to 30°C (36°F to 86°F).
Discard the unused portion 90 days after first opening.
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