EMA Prepares Sight-Loss Warning for Mounjaro and Trulicity After the US Orders One for All GLP-1 Drugs

The European Medicines Agency (EMA) is preparing to add a rare eye condition that can cause permanent sight loss to the product information of two more diabetes and weight-loss medicines: Mounjaro (tirzepatide) and Trulicity (dulaglutide). The agency told Lusa on Friday, in a written reply published by Observador, that procedures are under way to include information on non-arteritic anterior ischaemic optic neuropathy (NAION) in the leaflets and prescribing information of both medicines.

No decision has been taken yet. The EMA told Lusa that the changes still need the approval of the European Commission. For Mounjaro, the proposal is to note that NAION cases have been seen with medicines of the GLP-1 class, based on clinical trial and post-marketing data. For Trulicity, the proposed change rests on safety reports and the medical literature.

What is new, and what is not

NAION is already a listed side effect of semaglutide. In June 2025 the EMA's Pharmacovigilance Risk Assessment Committee (PRAC) concluded that it is a very rare side effect of Ozempic, Rybelsus and Wegovy, affecting up to 1 in 10,000 people. Large studies pointed to roughly double the risk in adults with type 2 diabetes taking semaglutide, about one extra case per 10,000 years of treatment.

What changes now is the reach. The current EU product information for Mounjaro (last updated 21 September 2026) and Trulicity (last updated 30 January 2026) does not mention NAION; the Ozempic leaflet does.

The trigger was American. On 9 November the US Food and Drug Administration ordered a NAION warning on every GLP-1 medicine it has approved, tirzepatide included. Its analysis of 126 clinical trials found 6.4 cases per 100,000 patient-years on GLP-1 drugs against 3.8 on placebo or other diabetes treatments. Neither the PRAC meeting of 26 to 29 October nor the EMA's human medicines committee (CHMP) meeting of 9 to 12 November lists NAION in its published highlights, and the EMA's reply to Lusa named only Mounjaro and Trulicity, not liraglutide medicines such as Saxenda.

What patients in Portugal should do

• Know the symptoms. The FDA describes sudden, painless loss of vision in one eye, often noticed on waking; blurred or missing patches of vision; colours that look washed out; and hazy central vision.
• Act quickly. The EMA's advice for semaglutide is to contact your doctor without delay if your sight drops suddenly or worsens fast. If NAION is confirmed, semaglutide is stopped.
• Do not stop on your own. Nothing has been withdrawn, and the risk is very small. Raise any concern with the doctor who prescribed the medicine, particularly if you smoke or have high blood pressure, sleep apnoea or kidney disease, which the FDA lists as possible risk factors.
• Report it. Anyone can report a suspected side effect directly to the Autoridade Nacional do Medicamento e Produtos de Saúde (INFARMED, the medicines regulator) through its Portal RAM; reports feed the EU database the EMA uses to detect rare effects. Lusa reported that INFARMED has received on average about one report a day on these medicines this year.

Women taking Mounjaro have a separate change to note. At its November meeting the CHMP adopted a letter to doctors warning that it may affect how reliably the contraceptive pill works. Women on the pill are advised to add a barrier method for four weeks after starting Mounjaro and after each dose increase, or to switch to a non-oral method.