Sabril ^*

Sabril (generic name: vigabatrin) is an FDA-approved antiepileptic medication primarily used to treat refractory complex partial seizures in adults and children aged 2 years and older who have not responded adequately to alternative treatments. It is also indicated as monotherapy for infantile spasms in pediatric patients aged 1 month to 2 years. Due to the risk of permanent vision loss, Sabril is prescribed when the potential benefits outweigh the risks.

Mechanism of Action

Vigabatrin functions as an irreversible inhibitor of gamma-aminobutyric acid (GABA) transaminase, the enzyme responsible for the degradation of GABA. By inhibiting this enzyme, Sabril increases GABA levels in the brain, enhancing inhibitory neurotransmission and reducing seizure activity.

Clinical Benefits

In clinical trials, Sabril has demonstrated efficacy in reducing seizure frequency in patients with refractory complex partial seizures. For infantile spasms, vigabatrin has been effective in achieving spasm cessation and improving developmental outcomes. However, the risk of permanent vision loss necessitates careful patient selection and monitoring.

Additional Considerations

Sabril is available only through a restricted program called the Risk Evaluation and Mitigation Strategy (REMS). Regular vision assessments are recommended before and during treatment. Patients should be advised to report any visual disturbances promptly.

Caution

Sabril may cause fetal harm. Women of childbearing potential should use effective contraception during treatment. If a patient plans to become pregnant or falls pregnant during treatment with Sabril, the risks and benefits of continuing treatment should be discussed with a healthcare provider. They are also advised to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry, where they can be advised on the suitability of the medication prescribed.

Dosage

Sabril can be taken with or without food. If a dose is missed, take it as soon as remembered unless it is close to the next scheduled dose. Do not double-dose to make up for a missed one. The usual dosage is:

• Refractory Complex Partial Seizures (Adults): The initial recommended dose for patients weighing more than 60 kg is 500 mg taken twice daily (total of 1,000 mg/day). Based on response and tolerability, the dose may be increased in increments of 500 mg/day at weekly intervals, up to a maximum of 3,000 mg/day.
• Refractory Complex Partial Seizures (Pediatric patients 2–16 years): The starting dose is 25 mg/kg/day, divided into two doses. The dose can be adjusted based on clinical response and tolerability, not exceeding 3,000 mg/day.
• Infantile Spasms: The initial dose is 50 mg/kg/day, divided into two doses. The dose may be titrated by 25–50 mg/kg/day increments every 3 days, up to a maximum of 150 mg/kg/day.

Storage

Keep Sabril tablets and sachets in their original container out of bright light and away from moisture. Store at 20-25°C (68-77°F).

Frequent Questions About Sabril

How long does Sabril take to work?

The response time varies. Patients with refractory complex partial seizures may see improvement within weeks to months. For infantile spasms, clinical trials suggest that spasms may stop within 7-14 days of starting treatment. However, the risk of adverse effects, such as decreased visual acuity, necessitates close monitoring.

Can vigabatrin cause weight gain?

Yes, weight gain is a common side effect of vigabatrin, occurring in approximately 15-20% of patients. The mechanism is unclear but may be related to metabolic changes and increased appetite due to GABA modulation.

Is Sabril the best treatment for infantile spasms?

Sabril is considered a first-line therapy for infantile spasms, particularly in cases associated with tuberous sclerosis complex (TSC). However, its use is carefully weighed against the risk of permanent vision loss. Alternative treatments include ACTH (adrenocorticotropic hormone) therapy.