TOPLINE:

Use of topiramate was associated with a significantly higher risk for glaucoma than the other antiseizure medications valproate and lamotrigine, especially in women and patients with epilepsy, but not in men or those with migraine, new research showed.

METHODOLOGY:

• Two retrospective, population-based, active-comparator cohort studies used electronic health records from a UK database for patients with epilepsy or migraine who initiated topiramate (n = 688; mean age, 38.5 years; 76% women), valproate (n = 4490; mean age, 44 years; 48% women), or lamotrigine (n = 4179; mean age, 41 years; 62% women).
• One cohort compared new users of topiramate and valproate, and the other compared new users of topiramate and lamotrigine.
• The primary outcome was the incidence of glaucoma, which included diagnoses of primary open-angle glaucoma, angle-closed glaucoma, and related conditions.
• Patients were followed for up to 1 year from treatment initiation or the earliest of incidence of glaucoma, death, drug discontinuation or switch, or study end.

TAKEAWAY:

• Use of topiramate was associated with a higher risk for glaucoma than the use of valproate (adjusted hazard ratio [aHR], 2.7; P = .03) or lamotrigine (aHR, 3.6; P < .001). The risk increased steeply beginning at day 100 and again at day 200 of initiation for topiramate vs valproate and at around day 200 for topiramate vs lamotrigine.
• Women using topiramate had a fivefold higher risk for glaucoma than women using valproate (aHR, 5.3; P = .01) or lamotrigine (aHR, 5.7; P < .001)
• Patients with epilepsy who used topiramate also had a higher glaucoma risk than those who used valproate (aHR, 2.2; P = .04) or lamotrigine (aHR, 5.1; P < .001).
• No significant associations were found between topiramate use and glaucoma risk in men or in patients with migraine.

IN PRACTICE:

“Sex-specific risk should be considered when selecting antiseizure therapy,” the investigators wrote. 

“The elevated risk in epilepsy suggests an indication-specific effect: Avoiding topiramate could prevent 26 cases per 1000 epilepsy patients vs valproate. In female patients with epilepsy who are at the intersection of both high-risk groups, the absolute number of preventable cases is likely to be even greater,” they added.

SOURCE:

The study was led by Cuiling Wei, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China. It was published online on January 10 in Epilepsia.

LIMITATIONS:

The study may have had residual confounding from unmeasured factors, such as family history of glaucoma or baseline ocular parameters. Misclassification of exposures and outcomes was possible because glaucoma ascertainment relied on recorded diagnoses, procedures, or antiglaucoma prescriptions, which may have underreported mild or asymptomatic cases that did not prompt primary care intervention. Subgroup analyses were constrained by small event numbers, leading to imprecise estimates. Additionally, the UK-based cohort may have limited generalizability to other populations.

DISCLOSURES:

The study did not receive any funding. The investigators reported having no relevant conflicts of interest. 

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.