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(vigabatrin) Tablets and Powder for Oral Solution
- SABRIL causes permanent bilateral concentric visual field constriction. Because assessing vision may be difficult in infants and children, the frequency and extent of vision loss is poorly characterized in these patients. For this reason, the risk described below is primarily based on the adult experience.
- Based upon adult studies, 30 percent or more of patients can be affected, ranging in severity from mild to severe, including tunnel vision to within 10 degrees 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 after starting treatment, even after months or years.
- Symptoms of vision loss from SABRIL are unlikely to be recognized by patients or caregivers before vision loss is severe. Vision loss of milder severity, while often unrecognized by the patient or caregiver, can still adversely affect function.
- The risk of vision loss increases with increasing dose and cumulative exposure, but there is no dose or exposure known to be free of risk of vision loss.
- Unless a patient is formally exempted from periodic ophthalmologic assessment as documented in the SHARE program, vision should be assessed to the extent possible at baseline (no later than 4 weeks after starting SABRIL) and at least every 3 months during therapy. Vision assessment is also required about 3 to 6 months after the discontinuation of SABRIL therapy.
- Once detected, vision loss due to SABRIL 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.
- It is possible that vision loss can worsen despite discontinuation of SABRIL.
- Because of the risk of visual loss, SABRIL should be withdrawn from patients with refractory complex partial seizures who fail to show substantial clinical benefit within 3 months of initiation and within 2-4 weeks of initiation for patients with infantile spasms, or sooner if treatment failure becomes obvious. Patient response to and continued need for SABRIL should be periodically reassessed.
- SABRIL should not be used in patients with, or at high risk of, other types of irreversible vision loss unless the benefits of treatment 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.
- SABRIL should not be used with other drugs associated with serious adverse ophthalmic effects such as retinopathy or glaucoma unless the benefits clearly outweigh the risks.
- 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.
- The lowest dose and shortest exposure to SABRIL consistent with clinical objectives should be used.
Because of the risk of permanent vision loss, SABRIL is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the SHARE Program [see WARNINGS AND PRECAUTIONS]. Further information is available at [www.sabril.net or 1-888-45-SHARE].
SABRIL (vigabatrin) is an oral antiepileptic drug and is available as white film-coated 500 mg tablets and as a white to off-white granular powder for oral solution in packets of 500 mg.
The chemical name of vigabatrin, a racemate consisting of two enantiomers, is (±) 4-amino-5-hexenoic acid. The molecular formula is C6H11NO2 and the molecular weight is 129.16. It has the following structural formula:
Vigabatrin is a white to off-white powder which is freely soluble in water, slightly soluble in methyl alcohol, very slightly soluble in ethyl alcohol and chloroform, and insoluble in toluene and hexane. The pH of a 1% aqueous solution is about 6.9. The n-octanol/water partition coefficient of vigabatrin is about 0.011 (log P=-1.96) at physiologic pH. Vigabatrin melts with decomposition in a 3-degree range within the temperature interval of 171°C to 176°C. The dissociation constants (pKa) of vigabatrin are 4 and 9.7 at room temperature (25°C).
Each SABRIL tablet contains 500 mg of vigabatrin. The inactive ingredients are hydroxypropyl methylcellulose, magnesium stearate, microcrystalline cellulose, polyethylene glycols, povidone, sodium starch glycolate, and titanium dioxide.
SABRIL powder for oral solution is available as white to off-white granular powder for oral administration. Each packet contains 500 mg of vigabatrin. The inactive ingredient is povidone.
What are the possible side effects of vigabatrin (Sabril)?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have a serious side effect such as:
- any change in your vision, no matter how mild;
- back and forth eye movements you cannot control;
- pale skin, feeling light-headed or short of breath, rapid heart rate, trouble concentrating;
- worsening seizures; or
- confusion, mood or behavior changes, depression, thoughts about suicide or hurting...
Last reviewed on RxList: 11/18/2013
This monograph has been modified to include the generic and brand name in many instances.
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