Summary: Researchers have identified a concerning safety signal linking widely used glucagon-like peptide-1 (GLP-1) receptor agonists—semaglutide, tirzepatide and liraglutide—to a measurable rise in clinically significant hypotensive episodes. These episodes include severe dizziness, fainting and traumatic falls, particularly among older adults and people with Type 2 diabetes.
Using electronic health records from more than 42,000 adults who were already prescribed at least two classes of blood pressure medications, the study team observed a rapid, statistically significant increase in documented low blood pressure events within six months of initiating a GLP-1 receptor agonist. The rise in hypotensive events persisted at 12 months and was most pronounced in adults aged 65 and over and in people with Type 2 diabetes.
Study overview and clinical context
GLP-1 receptor agonists are widely prescribed for weight loss, glycemic control and cardiovascular risk reduction. While these drugs provide important benefits for many patients, the Northwestern Medicine team found that starting GLP-1 therapy in patients already receiving multiple antihypertensive medications often correlated with an increase in symptomatic or clinically recorded hypotension. The dataset included formal diagnoses of low blood pressure, systolic readings below 90 mm Hg, new prescriptions for hypotension treatments and acute events such as dizziness, syncope and falls.
Key findings
- Within six months of starting a GLP-1, the rate of documented hypotensive events rose from 8.7% to 10.2% among patients on multi-drug antihypertensive regimens.
- The elevated risk remained statistically significant at 12 months, with hypotensive events increasing from 13.6% to 14.3%.
- Adults aged 65 and older represented 37% of the study population but accounted for 53% of hypotensive events, highlighting age-related vascular vulnerability.
- Patients with Type 2 diabetes made up 63% of the cohort yet represented 75% of those who experienced fainting or low blood pressure spikes, consistent with diabetes-related autonomic dysfunction.
- Secondary analyses indicated that weight loss alone did not explain the increase in hypotensive events, suggesting direct cardiovascular or autonomic effects of GLP-1 receptor agonists beyond their metabolic benefits.
Clinical implications
The authors emphasize that these hypotensive events are largely recognizable and, in many cases, preventable. Because GLP-1 drugs can rapidly improve metabolic control and lower blood pressure, clinicians should view GLP-1 initiation as an opportunity to reassess and often de-escalate antihypertensive therapy. Failure to adjust existing blood pressure medications can result in over-treatment and dangerous drops in pressure, especially in older adults and in patients with autonomic impairment from diabetes.
The investigators also raised concerns about remote, automated prescribing models that do not include routine blood pressure monitoring or structured follow-up. Without active clinical supervision, patients may remain unaware of progressive hypotension until they experience dizziness, syncope or an injury from a fall.
Q&A with Dr. Micah Eimer (study senior author)
Q: Why investigate this interaction between GLP-1s and blood pressure medications?
“GLP-1s reduce cardiovascular risk and are vitally important for many patients, but in clinical practice I observed multiple patients developing lightheadedness and low blood pressure after starting these drugs. Given the severity of outcomes from hypotension—falls, head injuries, car accidents and even death—we needed to study whether this was a broader pattern.”
Q: How clinically meaningful is the observed increase in hypotensive events?
“The roughly 1.5% absolute increase at six months is statistically significant and clinically relevant because the consequences of hypotension can be severe. The key message is that these events are detectable and often preventable if clinicians proactively monitor blood pressure and adjust other medications when initiating a GLP-1.”
Q: What should patients know?
“Patients should be aware that if they start a GLP-1 and begin to feel dizzy or faint, or notice lightheadedness when standing, they should contact their prescribing clinician. Remote prescribers may not be checking blood pressure or asking about orthostatic symptoms; patients should seek direct clinical follow-up to reduce risk.”
Q: Why are older adults and people with diabetes most affected?
“Older adults are more sensitive to blood pressure changes because of arterial stiffness and existing vascular disease. People with long-standing Type 2 diabetes can have autonomic dysfunction, impairing blood pressure regulation. In addition, there may be drug-specific mechanisms we do not yet fully understand.”
Practical recommendations
- When initiating a GLP-1 in a patient on multiple antihypertensives, perform an early medication review and consider structured de-escalation of blood pressure drugs where appropriate.
- Monitor standing and seated blood pressure within weeks of starting GLP-1 therapy and educate patients to report lightheadedness, presyncope, syncope or falls promptly.
- Avoid relying solely on automated, remote prescribing without a plan for ongoing blood pressure monitoring and follow-up.
Publication and source
The peer-reviewed findings will be presented at ENDO 2026. Source: Northwestern University. Study title: “GLP1 Receptor Agonists and the Risk of Significant Hypotension Among Patients with Metabolic Cardiovascular Renal Disease: Too Much of A Good Thing?”
Editorial notes
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full by the reporting team.
- Additional clinical context was added by staff for clarity and patient safety emphasis.
About this research
Author: Ben Schamisso
Source: Northwestern University
Contact: Ben Schamisso – Northwestern University
Image: The image is credited to Neuroscience News