What the product information says
Neither the US label nor the European summary lists deep vein thrombosis, pulmonary embolism or any other blood clot as a Victoza® reaction, in trials or in postmarketing reports. [1][2] The Canadian monograph lists pulmonary embolism under “less common clinical trial adverse reactions”, a list that also includes heart, brain and cancer events, with no rate and no statement that the drug caused it. [3]
The LEADER trial, which supports Victoza®’s US approval for lowering cardiovascular risk in type 2 diabetes with heart disease, followed thousands of people for years, but the labels do not report clot outcomes from it. [1]
| Source | Finding | Type and limits |
|---|---|---|
| US label [1] | Not listed | Prescribing information |
| EU SmPC [2] | Not listed | Summary of product characteristics |
| Canada, section 8.3 [3] | Pulmonary embolism among less common trial events | No rate; causality not stated |
| FDA reports, 2020–2025 [4] | No clot signal for GLP-1 class; liraglutide higher than other GLP-1 drugs | Voluntary reports; cannot show cause |
| 39 randomized trials [5] | Venous clots OR 1.19 (not significant); DVT OR 1.64 | GLP-1 class; not liraglutide alone |
| 27 placebo-controlled trials [6] | Venous clots RR 0.70 (not significant); lung clots RR 0.60 | GLP-1 class; not liraglutide alone |
| 6 studies in diabetes vs DPP-4 inhibitors [7] | Venous clots HR 0.78 | Mostly observational; moderate risk of bias |
What the larger analyses found
Trial meta-analyses. A 2025 analysis of 39 randomized trials with 70,499 people found a non-significant trend towards more venous clots on GLP-1 medicines, a significant rise in deep vein thrombosis, especially in trials longer than 18 months and in cardiovascular outcome trials, the design LEADER used, and no link with pulmonary embolism. [5] Another 2025 analysis, limited to 27 placebo-controlled trials with 84,003 people, found no significant difference in venous clots overall and a lower risk of pulmonary embolism. [6] Neither abstract reports liraglutide separately. [5][6]
Real-world data in diabetes. A 2026 meta-analysis of six studies in adults with diabetes found GLP-1 medicines linked with a lower risk of venous clots than DPP-4 inhibitors, another common diabetes drug class; the authors called the evidence limited. [7]
Reporting data. A 2026 analysis of US FDA reports found that GLP-1 medicines as a group were reported for clots less often than other drugs, less often than orlistat for venous clots and less often than SGLT-2 inhibitors overall; within the class, liraglutide had higher reporting ratios than the others. [4] Such reports reflect what is sent in, so they cannot give risk or prove cause. [4]
A liraglutide trial that measured clotting
One randomized trial looked directly at clotting markers with liraglutide at the Victoza® dose. In 72 women with polycystic ovary syndrome, a condition linked with a higher clot risk, liraglutide 1.8 mg a day for 26 weeks caused about 5% weight loss; thrombin generation changed within the liraglutide group but not differently from placebo, and there was a trend towards better clot breakdown. [8] The authors read this as a possible reduction in clotting tendency that needs larger studies. [8] It measured blood tests, not actual clots.
If you already take a blood thinner
This is the Victoza®-specific point. Europe states that no interaction study with warfarin has been done and that, for medicines with a narrow safe range such as warfarin, a relevant interaction cannot be excluded; it recommends more frequent INR monitoring after starting liraglutide in people on warfarin or other coumarin medicines. [2] The EU leaflet tells patients that more frequent blood tests may be needed, and Canada includes a similar caution. [2][3] The US label does not mention warfarin specifically but asks for caution with oral medicines because of the slower stomach emptying. [1]
Vomiting and diarrhoea, the most common early Victoza® effects, can also affect how oral medicines are absorbed; Europe notes this for severe diarrhoea. [2]
Everyday risk factors
CDC lists the main risk factors for deep vein thrombosis and pulmonary embolism: injury to a vein from fractures or major surgery; slow blood flow from bed rest, a leg cast or long periods of sitting; higher oestrogen from contraceptives, hormone therapy or pregnancy; heart disease, lung disease, cancer and inflammatory bowel disease; a previous clot, an inherited clotting disorder or family history; older age; and overweight or obesity. [10] The risk grows when several factors are present at once. [10]
Several of these are common in people prescribed Victoza®, such as heart disease and excess weight. Dehydration is not on the CDC list, but it is a known Victoza® risk in its own right because of its link with kidney injury. [1][10]
What the sources describe
- Move around as soon as you can after surgery, illness or bed rest. [9]
- On journeys longer than 4 hours, get up and walk every 1 to 2 hours, wear loose clothing and exercise your calves while seated. [9]
- If you are at higher risk, ask your doctor about compression stockings or anticoagulant medicine, as CDC suggests. [9]
- If you take warfarin, tell the clinic monitoring your INR when Victoza® is started or changed. [2]
- Tell your surgical team you use Victoza® before any planned operation, as the US label asks. [1]
Victoza® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk A/S.
When to get help
The signs and contact information below come from this article’s sourced guidance.