What the Foundayo™ documents cover
Foundayo™ is a once-daily orforglipron tablet approved in the US for weight management [1]. Neither the Prescribing Information nor the Medication Guide mentions blood clots, deep vein thrombosis (DVT) or pulmonary embolism (PE) [1][2]. Several entries still touch the topic, because they concern the heart, other medicines or surgery. The EMA’s committee issued a positive opinion in October 2026, but no EMA product information exists yet, and Health Canada lists no Foundayo™ product [3][4].
| Topic | What the US label says |
|---|---|
| DVT, PE or other clots | No entry in warnings or adverse reactions [1][2] |
| Heart rate | Tachycardia 3% vs 0.9% on placebo; average rise of 4 to 5 beats per minute [1] |
| Low blood pressure | Hypotension 2% vs 0.5%; 4% among people on blood pressure medicines [1] |
| Birth control pills | Absorption may fall for 30 days after the first dose and after each step up; a non-oral or added barrier method is advised for those windows [1] |
| Other oral medicines | Slower stomach emptying may change absorption; no specific blood thinner interaction is listed [1] |
| Surgery and sedation | Tell providers about Foundayo™ before planned procedures [1][2] |
Clot events in the orforglipron registries
The ATTAIN weight trials and the ACHIEVE-3 diabetes trial list every serious adverse event; ACHIEVE-5 lists every event of any kind [5][6][7][8]. Trial doses of 6, 12 and 36 mg in ATTAIN correspond to Foundayo™ 5.5, 9 and 17.2 mg in the label [1].
| Trial [source] | Comparison group | Orforglipron groups |
|---|---|---|
| ATTAIN-1, obesity, 72 weeks, serious events [5] | Placebo: PE 1/948; DVT 0/948 | 12 mg: DVT 2/724, PE 1/724, retinal vein occlusion 1/724; 6 mg and 36 mg: none |
| ATTAIN-2, obesity with type 2 diabetes, serious events [6] | Placebo: mesenteric vein clot 1/628; portal vein clot 1/628 | 36 mg: PE 1/321; 6 mg and 12 mg: none |
| ACHIEVE-3, open label vs oral semaglutide, serious events [7] | Semaglutide 7 mg: DVT 1/426; 14 mg: none | 36 mg: DVT 1/423; 12 mg: none |
| ACHIEVE-5, with insulin, all events [8] | Placebo: none | 3 mg: thrombosis 1/137 (serious) and thrombophlebitis 1/137; 12 mg: clot in a heart chamber 1/132; 36 mg: none |
Reading the clot counts
- Across these four trials, clot events were single cases or pairs in groups of more than 100 people, on orforglipron, placebo and oral semaglutide alike [5][6][7][8].
- The two DVTs in ATTAIN-1 were both on 12 mg, with none on the higher 36 mg dose, so the counts show no dose pattern [5].
- None of these trials was designed to measure clots, and the label reports no clot rate [1].
- The ATTAIN trials enrolled adults with obesity, a group NHLBI describes as having higher clot risk to begin with [14].
Heart attacks and strokes: ACHIEVE-4
Clots in arteries narrowed by plaque can block blood flow to the heart or brain [14], and heart attacks and strokes were the focus of ACHIEVE-4. The trial randomised 2,749 adults with type 2 diabetes and established heart or kidney disease to orforglipron, up to a 36 mg capsule equivalent to the 17.2 mg tablet, or to insulin glargine, both open label [9].
Over a median of two years, the combined outcome of cardiovascular death, non-fatal heart attack, non-fatal stroke or hospital stay for unstable angina occurred in 57 of 1,358 people on orforglipron (4.2%) and 67 of 1,343 on insulin glargine (5.0%), a hazard ratio of 0.84 [9]. That met the trial’s test of being no worse than insulin. It did not show a benefit, because the confidence interval crossed 1, and it was run in type 2 diabetes, which the US Foundayo™ label does not cover [1][9].
What studies of other GLP-1 medicines found
Two 2025 meta-analyses of randomised trials looked at venous clots across the GLP-1 class. Pooling 27 placebo-controlled trials with 84,003 patients, one found no significant change in overall clot risk and a lower risk of pulmonary embolism [10]. Pooling 39 trials with 70,499 participants, the other found more DVTs on GLP-1 medicines, about 25 extra events per 10,000 person-years, mainly in trials longer than 18 months and in cardiovascular outcome trials, with no link to pulmonary embolism [11].
Their literature searches ended in 2024, and both pooled other GLP-1 medicines rather than orforglipron [10][11]. They show the class question is unsettled; they cannot tell you what Foundayo™ does.
When a Foundayo™ effect looks like a clot symptom
MedlinePlus lists a fast heart rate, dizziness or fainting, and low blood pressure among the possible signs of a pulmonary embolism [13]. The Foundayo™ label lists a fast heart rate in 3% and low blood pressure in 2% of treated adults, and dizziness in 4% against 3% on placebo [1]. The overlap matters in one direction: a racing heart on its own is a known tablet effect, but a racing heart with sudden chest pain, breathlessness or coughing blood is an emergency, whatever medicine you take [13].
A swollen, red, warm or painful leg, usually on one side, is the typical sign of DVT and is not a Foundayo™ effect [12][15]. NHLBI asks you to call your provider right away if you think you may have clot symptoms [15].
Risk factors that matter more
NHLBI and MedlinePlus list the main reasons clots form; most people who develop one have more than one [12][14]:
- Not moving for long periods, including flights of more than four hours, bed rest and recovery after surgery; risk is highest in the first three months after an operation.
- A past clot, a family history of clots or an inherited clotting disorder.
- Cancer and its treatment, heart failure or a recent heart attack, kidney disease, diabetes and high blood pressure.
- Obesity, and older age: NHLBI says the chance nearly doubles every 10 years after 40.
- Pregnancy, giving birth within the last six months, and taking estrogen or birth control pills.
- Smoking, which raises the risk further in people taking estrogen.
Practical points on Foundayo™
MedlinePlus suggests moving your legs often on long journeys and not smoking, and NHLBI suggests asking about a prevention plan before major surgery [12][14]. Foundayo™ adds one request of its own: tell your providers you take it before any planned surgery or procedure [1][2].
If you take a blood thinner, the Foundayo™ label names no specific interaction, but it notes that delayed stomach emptying may affect how oral medicines are absorbed [1]. MedlinePlus advises asking your provider whether your blood thinner needs to be taken on an empty stomach [12]; list every medicine for the prescriber and pharmacist, as the Medication Guide asks [2].
If your prescriber suggests changing birth control because of the oral contraceptive advice in the label, clot history is worth raising at the same time, since MedlinePlus lists estrogen and birth control pills among DVT risk factors [1][12].
Foundayo™ is a trademark of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Eli Lilly and Company.
When to get help
The signs and contact information below come from this article’s sourced guidance.
Emergency
- Chest pain that worsens on deep breathing, sudden shortness of breath, coughing up blood or fainting
Contact: Emergency services (911 or your local number)
MedlinePlus, pulmonary embolus [13]
- A racing heart together with chest pain or breathlessness
Contact: Emergency services
MedlinePlus, pulmonary embolus [13]
- Swelling of the face, lips or throat, trouble breathing or a very rapid heartbeat after a dose
Contact: Stop Foundayo™ and get medical help right away
Foundayo™ Medication Guide [2]