Vigafyde Dosage

Generic name: VIGABATRIN 100mg in 1mL
Dosage form: oral solution
Drug class: Gamma-aminobutyric acid analogs

Medically reviewed by Drugs.com. Last updated on Feb 6, 2025.

2.1 Important Dosing and Administration Instructions

Dosing

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. VIGAFYDE does not require additional reconstitution or dilution prior to administration.

Use the lowest dosage and shortest exposure to VIGAFYDE consistent with clinical objectives.

The VIGAFYDE dosing regimen depends on weight.

Monitoring of VIGAFYDE plasma concentrations to optimize therapy is not helpful.

Administration

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.

2.2 Recommended Dosage for Infantile Spasms

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).

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 mg (8.25 mL) twice daily
12	300 mg (3 mL) twice daily	900 mg (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.

2.3 Switching Between Other Vigabatrin Products and VIGAFYDE

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).

2.4 Discontinuation of VIGAFYDE

Avoid abrupt withdrawal. 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.