Serious Vision Disorder With Topiramate (TOPAMAX)

Health care professionals were notified on September 26, 2001 about an eye disorder in some patients taking the seizure drug topiramate (TOPAMAX). This condition is characterized by acute myopia (nearsightedness) and secondary-angle closure glaucoma. Glaucoma, characterized by elevated pressure in the eye, can lead to permanent loss of vision if left untreated.

Topiramate was approved by the Food and Drug Administration (FDA) in December 1996 as adjunctive treatment for adults as well as pediatric patients aged 2 to 16 years with partial-onset seizures, or primary generalized tonic-clonic seizures. The drug has also recently received approval for use in patients two years of age and older with seizures associated with Lennox-Gastaut syndrome.

An unapproved, but common, use of topiramate is in the treatment of bipolar disorder (manic depressive illness) in combination with other drugs. Controlled clinical trials have not been conducted though uncontrolled case reports do suggest that topiramate may be useful in helping to manage this illness.

As of August 17, 2001, the FDA had received 23 reported cases of the ocular syndrome—22 adults and one younger patient. It is generally recognized that postmarketing data are subject to substantial under-reporting and the FDA conservatively estimates that for every serious reaction reported, 10 go unreported.

The symptoms of this adverse reaction have typically occurred within the first month of treatment, with patients reporting an acute onset of decreased visual acuity and ocular pain or both. Eye examinations have revealed myopia (nearsightedness), redness, shallowing of the anterior chamber and elevated ocular pressure, with or without pupil dilation. Fluid from lymph or blood vessels may displace the lens and iris of the eye, causing angle-closure glaucoma.

The primary treatment of this condition is to take the patient off topiramate as soon as possible—but only in consultation with the treating physician as there is the potential for increased seizure frequency.

The following has been added to the professional product labeling or “package insert” for topiramate:

WARNINGS

Acute myopia and secondary angle closure glaucoma

A syndrome consisting of acute myopia associated with secondary angle closure glaucoma has been reported in patients receiving TOPAMAX. Symptoms include acute onset of decreased visual acuity and/or ocular pain. Ophthalmologic findings can include myopia, anterior chamber shallowing, ocular hyperemia (redness) and increased intraocular pressure. Mydriasis [dilation of the pupil] may or may not be present. This syndrome may be associated with supraciliary effusion resulting in anterior displacement of the lens and iris, with secondary angle closure glaucoma. Symptoms typically occur within one month of initiating TOPAMAX therapy. In contrast to primary narrow angle glaucoma, which is rare under 40 years of age, secondary angle closure glaucoma associated with topiramate has been reported in pediatric patients as well as adults. The primary treatment to reverse symptoms is discontinuation of TOPAMAX as rapidly as possible, according to the judgment of the treating physician. Other measures, in conjunction with discontinuation of TOPAMAX, may be helpful. Elevated intraocular pressure of any etiology, if left untreated, can lead to serious sequelae including permanent vision loss.

The new labeling instructs physicians to inform their patients to seek immediate medical attention if they experience blurred vision or pain around the eye.

What You Can Do

Do Not stop taking topiramate without talking to your physician.

You should contact your physician immediately if you experience any of the symptoms described above.

Adverse drug reactions should be reported to the FDA MedWatch Program by phone 1-800-FDA-1088, by fax 1-800-FDA-0178, by mail MedWatch, HF-2, FDA, 5600 Fishers Lane, Rockville, MD 20852-9787, or via the Internet at www.fda.gov/medwatch.