Generic name: vigabatrin
Dosage form: powder, for oral solution
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2.1 Important Dosing Instructions
SABRIL is given orally with or without food. The SABRIL dosing regimen depends on the indication, age group, weight, and dosage form (tablets or powder for oral solution). Patients with impaired renal function require dose adjustment [see Dosage and Administration (2.4)].
SABRIL tablets and powder for oral solution are bioequivalent. Either tablet or powder can be used for CPS. Powder for oral solution should be used for IS; tablets should not be used for IS because of difficulty in the administration of tablets to infants and young children.
SABRIL powder for oral solution should be mixed with water prior to administration.
If using SABRIL powder for oral solution, physicians should review and discuss the Medication Guide and instructions for mixing and giving SABRIL with the patient or caregiver(s). Physicians should confirm that patients or caregiver(s) understand how to mix SABRIL powder with water and administer the correct daily dose. Empty the entire contents of each 500 mg packet into a clean cup, and dissolve in 10 mL of cold or room temperature water per packet (see Table 2). Administer the resulting solution using the 10 mL oral syringe supplied with the medication. The concentration of the final solution is 50 mg/mL. Discard the resulting solution if it is not clear (or free of particles) and colorless. Each individual dose should be prepared and used immediately. Discard any unused portion of the solution after administering the correct dose.
Monitoring of SABRIL plasma concentrations to optimize therapy is not helpful.
If a decision is made to discontinue SABRIL, the dose should be gradually reduced [see Warnings and Precautions (5.6)].
2.2 Refractory Complex Partial Seizures
Adults (Patients >16 Years of Age)
Treatment should be initiated at 1000 mg/day (500 mg twice daily). Total daily dose may be increased in 500 mg increments at weekly intervals depending on response. The recommended dose of SABRIL in adults is 3000 mg/day (1500 mg twice daily). A 6000 mg/day dose has not been shown to confer additional benefit compared to the 3000 mg/day dose and is associated with an increased incidence of adverse events.
In controlled clinical studies in adults with complex partial seizures, SABRIL was tapered by decreasing the daily dose 1000 mg/day on a weekly basis until discontinued [see Warnings and Precautions (5.6)].
Pediatric Patients 10 to 16 Years of Age
Treatment is based on body weight as shown in Table 1. Treatment should be initiated at a total daily dose of 500 mg/day (250 mg twice daily) and may be increased weekly to a total maintenance dose of 2000 mg/day (1000 mg twice daily). Patients weighing more than 60 kg should be dosed according to adult recommendations.
|Table 1. Pediatric CPS Dosing Recommendations|
| Body Weight
| Total Daily*
| Total Daily*
|25 to 60††||500||2000|
*Administered in two divided doses.
†Maintenance dose is based on 3000 mg/day adult-equivalent dose
†† Patients weighing more than 60 kg should be dosed according to adult recommendations
In a controlled study in pediatric patients with complex partial seizures, SABRIL was tapered by decreasing the daily dose by one third every week for three weeks [see Warnings and Precautions (5.6)].
2.3 Infantile Spasms
The initial daily dosing is 50 mg/kg/day given in two divided doses; 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 [see Use in Specific Populations (8.4)].
Table 2 below describes how many packets and how many milliliters (mL) of water will be needed to prepare each individual dose. The concentration after reconstitution is 50 mg/mL.
|Table 2. Number of SABRIL Packets and mL of Water Needed for Each Individual Dose|
| Individual Dose [mg]
[Given Twice Daily]
| Total Number of
| Total mL of Water
Required for Dissolving
|0 to 500||1 Packet||10 mL|
|501 to 1000||2 Packets||20 mL|
|1001 to 1500||3 Packets||30 mL|
Table 3 provides the volume of the 50 mg/mL dosing solution that should be administered as individual doses in infants of various weights.
|Table 3. Infant Dosing Table|
| Starting Dose
| Maximum Dose
|3||1.5 mL twice daily||4.5 mL twice daily|
|4||2 mL twice daily||6 mL twice daily|
|5||2.5 mL twice daily||7.5 mL twice daily|
|6||3 mL twice daily||9 mL twice daily|
|7||3.5 mL twice daily||10.5 mL twice daily|
|8||4 mL twice daily||12 mL twice daily|
|9||4.5 mL twice daily||13.5 mL twice daily|
|10||5 mL twice daily||15 mL twice daily|
|11||5.5 mL twice daily||16.5 mL twice daily|
|12||6 mL twice daily||18 mL twice daily|
|13||6.5 mL twice daily||19.5 mL twice daily|
|14||7 mL twice daily||21 mL twice daily|
|15||7.5 mL twice daily||22.5 mL twice daily|
|16||8 mL twice daily||24 mL twice daily|
In a controlled clinical study in patients with infantile spasms, SABRIL was tapered by decreasing the daily dose at a rate of 25 mg/kg to 50 mg/kg every 3 to 4 days [see Warnings and Precautions (5.6)].
2.4 Patients with Renal Impairment
SABRIL is primarily eliminated through the kidney.
Information about how to adjust the dose in infants with renal impairment is unavailable.
Pediatric patients 10 years and older, and adult patients
- Mild renal impairment (CLcr >50 - 80 mL/min): dose should be decreased by 25%
- Moderate renal impairment (CLcr >30 - 50 mL/min): dose should be decreased by 50%
- Severe renal impairment (CLcr >10 - 30 mL/min): dose should be decreased by 75%.
CLcr in mL/min may be estimated from serum creatinine (mg/dL) using the following formulas:
- Patients 10 to <12 years old: CLcr (mL/min/1.73 m2) = (K × Ht) / Scr
height (Ht) in cm; serum creatinine (Scr) in mg/dL
K (proportionality constant): Female Child (<12 years): K=0.55;
Male Child (<12 years): K=0.70
- Pediatric patients 12 years or older and adult patients: CLcr (mL/min) = [140-age (years)] × weight (kg) / [72 × serum creatinine (mg/dL)] (×0.85 for female patients)