Study links two GLP-1 weight-loss drugs to rare brain disorder
Research involving nearly 196,000 patients identified 15 cases of Wernicke encephalopathy, a serious condition linked to vitamin B1 deficiency, that were disproportionately associated with semaglutide and tirzepatide.
A large Israeli study of 195,979 patients found 15 instances of Wernicke encephalopathy (WE), a rare neurological disorder caused by severe vitamin B1 deficiency, occurring more frequently among users of two GLP-1 receptor agonists. The medications implicated were semaglutide, marketed as Ozempic, Wegovy and Rybelsus, and tirzepatide, sold as Mounjaro and Zepbound.
Most of the affected individuals had experienced gastrointestinal symptoms such as vomiting, loss of appetite or significant weight loss, which can lead to inadequate nutrition and reduced thiamine levels. Only two patients displayed the classic triad of WE symptoms—confusion, ataxia and ocular disturbances—highlighting the difficulty of clinical recognition.
The researchers described WE as a potentially rare adverse event but emphasized the need for clinicians to monitor patients on these drugs for signs of thiamine deficiency, as early treatment with vitamin B1 can prevent permanent brain damage and reduce mortality.
WE is traditionally associated with chronic alcoholism, bariatric surgery, severe malnutrition and other conditions that impair thiamine absorption. Without prompt treatment, the disorder can be fatal in up to 20% of cases, and a majority of survivors may suffer lasting neurological deficits.