Wegovy's Link to Rare Eye Condition Raises Safety Concerns Amid Weight Loss Surge

A new investigation reveals that Wegovy, a prominent drug for weight loss, appears to have a significantly elevated risk of a rare eye condition known as ischemic optic neuropathy (ION). This condition can lead to sudden vision loss due to decreased blood flow to the optic nerve.

Published in the British Journal of Ophthalmology, the study showcases Wegovy exhibiting the strongest links to ION among various semaglutide-based GLP-1 medications assessed. The researchers found that the risk associated with Wegovy was nearly five times greater than that associated with Ozempic, another popular semaglutide option.

Although instances of ION are considered rare, the researchers emphasize that these findings bring to light significant safety considerations as the use of GLP-1 medications expands globally. The team analyzed data from the US Food and Drug Administration’s Adverse Event Reporting System (FAERS) covering reports made between December 2017 and December 2024, an extensive review involving over 30.6 million adverse event reports.

Within these records, 31,774 reports involved semaglutide medications. The average age of individuals included in the reports was 56, with women making up 54% of the cases surveyed. The analysis examined multiple GLP-1 drugs, including Ozempic, Wegovy, and Rybelsus, the oral version of semaglutide, alongside tirzepatide drugs such as Mounjaro and Zepbound.

Wegovy, despite fewer overall reports compared to Ozempic due to its later approval, showed a remarkably strong association with ION. Specifically, 28 cases were linked to Wegovy, while 47 were connected to Ozempic. However, the odds of developing ION while on Wegovy were approximately 75 times higher than expected, compared to Ozempic's odds of 19 and generic semaglutide at 21.

Interestingly, no reports of ION surfaced for Rybelsus, implying potential differences in the formulation and administration of these medications. The researchers noticed marked variances between genders; men using Wegovy presented the highest risk, with odds 116 times higher than expected, while women showed a stronger association with Ozempic. Their analysis indicated that men had more than triple the odds of ION compared to women.

Several factors may account for the heightened risk observed with Wegovy. Notably, the drug is administered in a higher dosage and is delivered via injection, enabling it to act faster than oral medications. The researchers proposed that the elevated dose of Wegovy could lead to reduced blood supply to the optic nerve, driven by potential fluctuations in blood pressure, fluid loss, and autonomic nervous system instability.

However, the researchers were careful to note that a direct cause-and-effect relationship hasn't been established. They suggested that the slower absorption rates of Rybelsus likely account for the absence of reported cases of ION among its users. Media scrutiny surrounding Wegovy may also influence the frequency of reported side effects, potentially skewing the findings.

The limitations of the FDA's reporting system are critical to understanding these findings. It doesn't quantify how often ION occurs, nor does it provide detailed patient health data or disease severity insights. Despite this, the researchers argue that their findings present early signals suggesting that both the drug formulation and dosage could significantly impact the risk of ION.

"The study offers the first evidence linking the risk of ION to both formulation and dose, with Wegovy showing the strongest connection," the team emphasized. They called for urgent evaluations to better inform prescribing practices and regulatory policies.

Commentators in a related piece concurred, underscoring the need for comprehensive attention from eye care specialists as well as additional research. They noted, "The findings contribute to an increasing body of literature detailing ocular complications associated with anti-obesity medications, which necessitates further examination and clarification."

With obesity prevalence continuing to rise globally—29% of adults in the UK alone are classified as obese—the conversation surrounding GLP-1 medications is expanding. Research is branching out to explore cardiovascular benefits, reductions in stroke, and potential links to treating dementia.

The rise in prescriptions for these medications is expected to continue. However, the authors of the commentary raised concerns regarding prescribing these drugs to children over 12, noting that broader usage could lead to future increases in rare eye complications.

Despite these significant concerns, some studies suggest GLP-1 drugs may benefit certain ocular conditions, such as age-related macular degeneration and uveitis. Yet, caution is warranted, as these potential advantages must be balanced against the serious risks, including ION.