Sabril (Vigabatrin) is an antiepileptic drug primarily used for the treatment of refractory complex partial seizures and infantile spasms. While this medication has shown favorable efficacy in controlling specific types of epileptic seizures, it is accompanied by a series of side effects and medication-related risks that require special attention.
What Are the Side Effects of Sabril (Vigabatrin)?
Adverse Reactions in Adult Patients
The most common adverse reactions in adult patients taking Sabril include blurred vision, drowsiness, dizziness, abnormal coordination, tremors, and fatigue.
The incidence rates are as follows: blurred vision (13%), drowsiness (22%), dizziness (24%), tremors (15%), and fatigue (23%).
Unique Reactions in Pediatric Patients (Aged 2–16 Years)
Weight gain is one of the most prominent adverse reactions in pediatric patients aged 2–16 years, with an incidence rate of 15%.
Pediatric patients may also experience neurological symptoms such as drowsiness (6%), nystagmus (4%), and tremors (4%).
Reactions in Infants with Infantile Spasms (Aged 1 Month–2 Years)
Clinical observations in infants with infantile spasms (aged 1 month to 2 years) show that those taking Sabril are prone to side effects including drowsiness (45%), bronchitis (30%), ear infections (10%), and acute otitis media (10%).
Severe Side Effects of Sabril (Vigabatrin)
Permanent Vision Damage
Most serious warning: Sabril can cause permanent bilateral concentric visual field constriction, including tunnel vision, which may result in disability.
In some cases, Sabril may also damage the central retina and reduce visual acuity.
The onset of vision loss is unpredictable—it may occur within weeks or even earlier after starting treatment, at any time during treatment, or even months or years later.
Symptoms of vision loss are unlikely to be recognized by patients or caregivers before the vision loss becomes severe.
Even if detected, vision loss caused by Sabril is irreversible.
Neurological Risks
Abnormal MRI signal changes: Characteristic MRI signal changes have been observed in some infants treated for infantile spasms, manifested as increased T2-weighted signals and restricted diffusion, symmetrically involving the thalamus, basal ganglia, brainstem, and cerebellum.
Suicidal behavior and ideation: Similar to other antiepileptic drugs, Sabril may increase the risk of suicidal thoughts or behaviors in patients.
Severe Reactions in Other Systems
Anemia: In North American controlled trials, 6% of Sabril-treated patients reported anemia and/or met the criteria for potentially clinically significant hematological changes. An average decrease of approximately 3% in hemoglobin and 1% in hematocrit was observed.
Peripheral neuropathy: Sabril can cause symptoms of peripheral neuropathy in adult patients.
Precautions for Using Sabril (Vigabatrin)
Strict Requirements for Vision Monitoring
It is recommended to conduct vision assessments at baseline (no more than 4 weeks after starting Sabril treatment), at least every 3 months during treatment, and approximately 3–6 months after treatment discontinuation.
Warnings for Medication Use in Special Populations
Mild renal impairment (CLcr > 50–80 mL/min): The dose should be reduced by 25%.
Moderate renal impairment (CLcr > 30–50 mL/min): The dose should be reduced by 50%.
Severe renal impairment (CLcr > 10–30 mL/min): The dose should be reduced by 75%.
Pregnancy and lactation: Based on animal data, Sabril may cause fetal harm.
Special Reminder for Medication Discontinuation
Do not discontinue abruptly: Sabril should be discontinued gradually; sudden discontinuation may trigger withdrawal seizures.
Key Points for Patient Education
Regular vision monitoring is required during Sabril treatment.
Any changes in vision must be reported to healthcare providers immediately.
The emergence of suicidal thoughts or changes in behavior requires urgent medical attention.
