September, 2001: One of the medications that has been increasingly prescribed as a migraine preventive is the antiseizure medication Topamax (Topiramate), manufactured by Ortho-McNeil Pharmaceutical, Inc. Topamax is the same class drug as Depakote and Neurontin, which are also in use as migraine preventives. Depakote has been approved by the FDA for migraine prevention, particularly Depakote ER, which was developed in time-release form. Both Neurontin and Topamax are prescribed off-label, which means that there is anecdotal evidence enough to prescribe them for this use, but they have not yet been approved by the FDA for it. Off-Label prescribing is a fairly common practice with many drugs when there is evidence of their effectiveness for off-label conditions.
On September 26, 2001, Joseph Hulihan, M.D., Director of CNS Research at Ortho-McNeil Pharmaceutical, Inc. issued a warning statement to health care professionals warning of some startling potential side effects of Topamax. Postmarketing reports of these potential side effects indicate:
"Symptoms have typically occurred within the first month of therapy, with patients reporting an acute onset of decreased visual acuity and/or ocular pain. Eye examination revealed myopia, redness, shallowing of the anterior chamber and elevated ocular pressure, with or without pupil dilatation. Supraciliary effusion may displace the lens and iris anteriorly, secondarily causing angle closure glaucoma."1
The
following has now been added to Topamax prescribing information:
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 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 1
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.
If you are taking Topamax, call your doctor
immediately if you notice anything unusual in your vision, blurred vision, or
pain around the eye. If you need to consult a doctor about this issue, it may be
helpful to take them a copy of the warming letter, which you can find
HERE.
Ortho-McNeil has asked that any such incidents be reported to them:
"You can further our understanding of adverse events by reporting all cases to Ortho-McNeil at the contact numbers below or to the FDA MedWatch Program by phone 1-800-FDA-1088, by fax 1-800-FDA-0178, by mail (using postage-paid form) MedWatch, HF-2, FDA, 5600 Fishers Lane, Rockville, MD 20852-9787, or via www.fda.gov/medwatch."1
If you would like to read the entire letter sent to health care professionals, please click HERE.
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References:
1 Joseph Hulihan, M.D., Director of CNS Research at Ortho-McNeil Pharmaceutical, Inc. Letter to health care professionals, September 26, 2001.
