Some Vision Testing Options
There are many visual test options when monitoring for Sabril-induced vision loss. Perimetry is recommended, preferably by automated
threshold visual field testing. Test results can vary and must be carefully interpreted.
Some testing options for vision loss*1-4
||Developmental Age Appropriateness†
||Examiner moves stimuli through patient's visual field and maps field defects on a reference grid. More sensitive than confrontation testing.
(Octopus and Humphrey Visual field analyzers)1
||Automated visual field analyzer projects light stimuli, measures reaction, and maps the patient's visual field. An objective testing option.
||All ages; appropriate for infants
||Through an electrode placed on the eye, electrical activity in the retina is measured in response to a flash of light. An objective testing option that usually requires sedation in infants and young children.
|Optical coherence tomography
|Appropriate for any age other than infancy (in which OCT cannot be performed reliably) including patients with cognitive impairment
||Noncontact, noninvasive, painless imaging technique obtains high-resolution cross-sectional images of the retina in a short time (usually requires 1 to 2 minutes per eye when performed by an experienced technician).
||Children and those who cannot read
||Measures the eye's ability to see details at near and far distances and usually involves reading letters or looking at symbols of different sizes on an eye chart. Several types of visual acuity tests may be used.
* To be conducted by an ophthalmic professional with expertise in visual field interpretation and the ability to perform dilated indirect ophthalmoscopy of the retina.
â€ Cognitive age.
- Repeat testing is recommended:
- (1) if results are abnormal or uninterpretable, and (2) in the first few weeks of treatment to determine whether reproducible results can be obtained and to guide ongoing monitoring
- The diagnostic approach should be individualized for the patient and clinical situation, but for all patients, attempts to monitor periodically must be documented under the SHARE Program
- All patients must have a central visual acuity test
Important Safety Information
SABRIL® (vigabatrin) Tablets
SABRIL® (vigabatrin) for Oral Solution
SABRIL is indicated as adjunctive therapy for adult patients with refractory complex partial seizures (CPS) who have inadequately responded to several alternative treatments and for whom the potential benefits outweigh the risk of vision loss. SABRIL is not indicated as a first line agent for complex partial seizures.
SABRIL is indicated as monotherapy for pediatric patients 1 month to 2 years of age with infantile spasms (IS) for whom the potential benefits outweigh the potential risk of vision loss.
Important Safety Information
WARNING: VISION LOSS
See full Prescribing Information for complete boxed warning
- SABRIL causes progressive and permanent bilateral concentric visual field constriction in a high percentage of patients. In some cases, SABRIL may also reduce visual acuity
- Risk increases with total dose and duration of use, but no exposure to SABRIL is known that is free of risk of vision loss
- Risk of new and worsening vision loss continues as long as SABRIL is used, and possibly after discontinuing SABRIL
- Unless a patient is formally exempted, periodic vision assessment is required for patients on SABRIL. However, this assessment cannot always prevent vision damage
- Because of the risk of permanent vision loss, SABRIL is available only through a special restricted distribution program
SABRIL causes permanent vision loss in infants, children, and adults. Because assessing vision loss is difficult in children, the frequency and extent of vision loss in infants and children is poorly characterized.
In adults, SABRIL causes permanent bilateral concentric visual field constriction in 30% or more of patients that ranges in severity from mild to severe, including tunnel vision to within 10° of visual fixation, and can result in disability. In some cases, SABRIL also can damage the central retina and may decrease visual acuity. The onset of vision loss from SABRIL is unpredictable and can occur within weeks of starting treatment or sooner, or at any time during treatment, even after months or years. The lowest dose and shortest exposure to SABRIL should be used that is consistent with clinical objectives.
Because of the risk of permanent vision loss, SABRIL should be withdrawn from patients with IS who fail to show substantial clinical benefit within 2 to 4 weeks of initiation, or sooner if treatment failure becomes obvious, or adult patients treated for refractory CPS as adjunctive therapy who fail to show substantial clinical benefit within 3 months of initiation, or sooner if treatment failure becomes obvious. Patient response to and continued need for SABRIL should be periodically reassessed.
Unless a patient is formally exempted from periodic ophthalmologic assessment as documented in the SHARE program, vision assessment is required at baseline (no later than 4 weeks after starting SABRIL), at least every 3 months while on therapy and about 3-6 months after the discontinuation of SABRIL therapy. Once detected, vision loss is not reversible. It is expected that, even with frequent monitoring, some patients will develop severe vision loss. Drug discontinuation should be considered, balancing benefit and risk, if visual loss is documented.
Symptoms of vision loss from SABRIL are unlikely to be recognized by the patient, parent or caregiver before vision loss is severe. Vision loss of milder severity, although unrecognized by the patient, parent or caregiver may still adversely affect function. The possibility that vision loss from SABRIL may be more common, more severe, or have more severe functional consequences in infants and children than in adults, cannot be excluded.
SABRIL should not be used in patients with, or at high risk of, other types of irreversible vision loss or with other drugs associated with serious adverse ophthalmic effects such as retinopathy or glaucoma unless the benefits clearly outweigh the risks. The interaction of other types of irreversible vision damage with vision damage from SABRIL has not been well characterized, but is likely adverse.
In adult patients treated for CPS, dose adjustment is necessary in patients with renal impairment.
Abnormal MRI signal changes have been observed in some infants treated for IS with SABRIL. These changes generally resolved with discontinuation of treatment and in a few patients the lesion resolved despite continued use.
Antiepileptic drugs (AEDs), including SABRIL, increase the risk of suicidal thoughts or behavior. Adult patients should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior and/or any unusual changes in mood or behavior.
As with all AEDs, SABRIL should be discontinued gradually to avoid withdrawal seizures.
Vigabatrin is excreted in human milk and may cause serious adverse events in nursing infants. SABRIL should not be used during pregnancy unless the potential benefit justifies the potential risk to the fetus.
Pregnancy Registry: To provide information regarding the effects of in utero exposure to SABRIL, physicians are advised to recommend that pregnant patients taking SABRIL enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. This can be done by calling the toll-free number 1-888-233-2334, and must be done by patients themselves. Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/.
SABRIL has been shown to cause neurotoxicity, anemia, somnolence and fatigue, peripheral neuropathy, weight gain and edema. The most commonly observed adverse reactions reported in 2 add-on clinical studies of adults with refractory CPS treated with SABRIL as adjunctive therapy with the recommended dose of 3 g/day (≥10% and at least 5% greater than placebo, respectively) were dizziness (24% vs 17%), fatigue (23% vs 16%), somnolence (22% vs 13%), tremor (15% vs 8%), blurred vision (13% vs 5%), and arthralgia (10% vs 3%). A 6 g/day dose has not been shown to confer additional benefit compared to the 3 g/day dose and is associated with an increased incidence of adverse events.
The most common adverse events reported by >5% of infants taking SABRIL for IS occurring more frequently than placebo, respectively, in a randomized, placebo-controlled IS study with a 5-day double-blind treatment phase (n=40) were somnolence (45% vs 30%), bronchitis (30% vs 15%), ear infection (10% vs 5%), and acute otitis media (10% vs 0%).
Oral Solution: For more information, please see the full Prescribing Information including Boxed Warning, Medication Guide, and Dosing Instructions.
Solución oral: Para más información, vea por favor la información que prescribe completa incluyendo la advertencia encajonada, guía de la medicación, y las instrucciones de la dosificación.
Tablets: For more information, please see the full Prescribing Information including Boxed Warning and Medication Guide.
Tabletas: Para más información, vea por favor la información que prescribe completa incluyendo la advertencia encajonada, y guía de la medicación.
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.
- Harrington DO, Drake MV. The Visual Fields: Text and Atlas of Clinical Perimetry. St. Louis, MO: The CV Mosby Company; 1990.
- Kriss A, Russell-Eggitt I. Electrophysiological assessments of visual pathway function in infants. Eye. 1992;6:145-153.
- Pedut-Kloizman T, Pakter HM, Schuman JS, Szwartz JC, Hee MR. Ophthalmic diagnosis using optical coherence tomography. Ophthalmol Clin North Am. 1998;11(3):465-486.
- Vision tests. WebMD Web site. www.webmd.com/eye-health/vision-tests. Updated July 6, 2007. Accessed September 15, 2009.