Low dose-topiramate-induced acute bilateral reversible glaucoma : a case report

OBJECTIVE: To report possible rapid onset adverse events with low-dose topiramate BACKGROUND: Topiramate is an antiepileptic drug, also useful for migraine prophylaxis. Topiramate effects on ocular pressure are well known, generally linked to preexistent glaucoma and in most cases in a dose dependent way. DESIGN/METHODS: We observed the clinical evolution of visual disturbances appeared after 3 days of 25 mg topiramate daily intake in a young female migraineur RESULTS: After three days of assumption of a 25mg daily dose of topiramate for migraine prevention, previously non responding to amitriptyline, a 25 year-old caucasian woman developed, in about 12 hours, acute bilateral severe visual loss. She was unable to distinguish familial faces and to count fingers in both eyes. Intraocular pressure was 30 mm and 31 mm of Hg respectively in left and right eye. Conjunctival chemosis and corneal edema were present. A bilateral closed angle was found on gonioscopy. After three days therapy discontinuation, a quite complete resolution of the visual impairment was observed. Intraocular pressure after 24 hours discontinuation of topiramate was bilaterally 15mm of Hg, without any antiglaucoma therapy. After three days, visual acuity was normalized and conjunctival and corneal aspect was normal, such as ocular pressure. CONCLUSIONS/RELEVANCE: Topiramate is generally well tolerated, with only mild cognitive disturbances and, more often, mild-moderate paresthesias. Its effect on vision, causing an acute angle closure glaucoma with myopic visual disturbances, is well known, but generally this adverse event appears less quickly. Many cases occured within 2 weeks since the starting of the therapy. We have not found any other case in which symptoms appeared after only three days of treatment at 25mg dose per day and so severely. Patients treated with topiramate need to be cautioned about this potential, even uncommon side effect, and when the problem appears, the prophilaxys need to be discontinuated.