Foundayo™ and kidney stones

Where stones appear in Foundayo™ documents

Foundayo™ is a once-daily orforglipron tablet approved in the US for weight management ^[1]. A search of its Prescribing Information and Medication Guide for kidney stone, nephrolithiasis, urolithiasis or renal colic finds nothing ^[1][2]. The kidney warning in section 5.4 concerns sudden kidney injury after fluid loss, not stones, and the only stones discussed are gallstones under acute gallbladder disease ^[1].

There is no European or Canadian wording to compare yet. The EMA’s committee issued a positive opinion in October 2026, but no EMA product information exists so far, and Health Canada’s Drug Product Database has no Foundayo™ entry ^[3][4].

Serious stone events in the two weight trials

The label’s safety data come from ATTAIN-1 and ATTAIN-2, which tested orforglipron at 6, 12 and 36 mg, doses the label presents as Foundayo™ 5.5, 9 and 17.2 mg ^[1]. Their registry pages give every serious adverse event but show other events only when they reached 5% of a group, so a stone not classed as serious would not appear ^[5][6]. Each cell counts people with that term. One person can carry two terms, for example a stone and the colic it caused, so the figures should not be added together.

Trials that published every event

Smaller trials posted all adverse events, so stones that were not serious show up as well. ATTAIN-J enrolled Japanese adults with obesity; ACHIEVE-5 enrolled people with type 2 diabetes already using insulin glargine; ACHIEVE-3 compared orforglipron with oral semaglutide in type 2 diabetes and lists serious events in full ^[7][8][9]. Treating type 2 diabetes is outside the US Foundayo™ indication ^[1].

What the counts can and cannot tell you

• Stones appeared in placebo groups too, which is expected in adults with obesity, a group NIDDK describes as more likely to form stones ^{[5][6][7][15]}.
• The largest cluster, three ureter stones on 6 mg in ATTAIN-1, did not repeat on 12 or 36 mg, so the registry gives no sign of a dose pattern ^[5].
• ACHIEVE-3 recorded three serious stone events on orforglipron and none on oral semaglutide; with more than 400 people per group and an open-label design, that is too few to separate chance from effect ^[9].
• None of these trials set out to measure stones, and the label reports no stone rate the way it reports gallstones ^[1].

How Foundayo™ could, in theory, be involved

Supported by the label: fluid loss. On the 17.2 mg dose, vomiting was reported by 24% against 4% on placebo and diarrhoea by 25% against 11%, most often while the dose was being stepped up ^[1]. MedlinePlus calls not drinking enough fluid the biggest risk factor for kidney stones ^[13], and the Foundayo™ label already asks prescribers to watch kidney function in people losing fluids ^[1].

Plausible but unmeasured: drinking and eating less overall. The label says Foundayo™ decreases food intake through lower appetite ^[1]. No orforglipron study has measured urine volume or urine chemistry, so whether this matters for stones is unknown.

From GLP-1 class research, with mixed signals: a US Veterans Affairs cohort of people with diabetes linked GLP-1 medicines to more kidney stones than usual care ^[10]. A Medicare study of stone formers found no change in 24-hour urine measures that affect stone formation on GLP-1 medicines ^[11], and a clinic study of 44 stone formers losing weight on GLP-1-based treatment saw urine oxalate fall without any rise in stone-forming saturation ^[12]. None of these studies included orforglipron.

One fact specific to the tablet: after a single dose, less than 1% of orforglipron was recovered in urine, while 87% left through the feces ^[1]. That describes how the medicine is cleared; it does not show an effect on stone risk either way.

Common reasons stones form

NIDDK and MedlinePlus list factors that make stones more likely, whatever medicine you take ^[13][14]:

• Being male, a family history of stones, or a stone in the past.
• Not drinking enough liquids.
• Gout, long-lasting bowel inflammation, other digestive problems or earlier gastrointestinal surgery.
• Conditions that put extra calcium, oxalate or uric acid into urine, such as hyperparathyroidism.
• Long-term use of some medicines, including diuretics (water pills), topiramate and indinavir.
• Repeated urinary tract infections, which MedlinePlus links to struvite stones.

Stone pain or one of the label’s warnings?

Three kinds of pain can come up during Foundayo™ treatment, and each has its own route to care.

• Kidney stone: severe pain that starts and stops suddenly in the belly or the side of the back, sometimes spreading to the groin, often with blood in the urine, nausea or vomiting ^[13].
• Gallbladder: pain in the upper stomach, fever, yellowing of the skin or eyes, or clay-coloured stools; the Medication Guide asks you to report these right away ^[2].
• Pancreatitis: severe pain in the stomach area that will not go away, sometimes reaching the back, with or without vomiting; the Medication Guide says to stop Foundayo™ and call your provider right away ^[2].
• Back pain from a stone and from pancreatitis can feel alike, which is why lasting severe pain needs a clinician rather than a guess ^[2][13].

Prevention steps from NIH sources

NIDDK calls drinking enough liquid, mainly water, the most important thing you can do to prevent stones, and suggests asking a health professional how much is right for you ^[15]. It adds that being overweight raises stone risk, that the DASH eating pattern has been linked to fewer stones, and that more sodium and more animal protein make stones more likely ^[15].

If you have had a stone, NIDDK suggests finding out which type it was, because advice on sodium, animal protein, calcium and oxalate depends on it. Calcium from food does not raise the chance of calcium oxalate stones ^[14][15].

On Foundayo™, the Medication Guide asks you to drink fluids to lower the chance of dehydration and to tell your provider promptly about nausea, vomiting or diarrhoea that will not settle ^[2]. Each step up comes no sooner than 30 days after the last, and the label reports these reactions most often during dose escalation ^[1].

Foundayo™ is a trademark of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Eli Lilly and Company.

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