Mounjaro (Tirzepatide) Nausea Severity Grading Rubric

What the Mounjaro label actually reports

The nausea numbers come from the label's pool of two placebo-controlled trials: SURPASS-1 (tirzepatide alone) and SURPASS-5 (tirzepatide added to basal insulin with or without metformin). In that pool 718 adults with type 2 diabetes received Mounjaro and 235 received placebo, with a mean exposure to Mounjaro of 36.6 weeks [1].

Nausea was reported by 4% of the placebo group, 12% of the 5 mg group, 15% of the 10 mg group and 18% of the 15 mg group. The same table gives vomiting at 2%, 5%, 5% and 9%; diarrhea at 9%, 12%, 13% and 17%; decreased appetite at 1%, 5%, 10% and 11%; constipation at 1%, 6%, 6% and 7%; dyspepsia at 3%, 8%, 8% and 5%; and abdominal pain at 4%, 6%, 5% and 5% [1].

Those are adults. Mounjaro is also indicated for patients 10 years and older, where the maximum dose is 10 mg weekly, and the label states that adverse reaction incidences in the 97 pediatric patients treated were consistent with those described for adults [1].

What severity figures the label does give

The label's warnings section gives severe gastrointestinal adverse reactions as a pooled category: 1.3% at 5 mg, 0.4% at 10 mg, 1.2% at 15 mg and 0.9% on placebo [1]. That figure covers gastrointestinal reactions as a group.

The label also gives a broader count of any gastrointestinal adverse reaction — 37.1% at 5 mg, 39.6% at 10 mg and 43.6% at 15 mg versus 20.4% on placebo — and reports that 3.0%, 5.4% and 6.6% of patients stopped treatment because of gastrointestinal adverse reactions, versus 0.4% on placebo [1]. Those figures cover discontinuation because of any gastrointestinal adverse reaction, not nausea alone.

What is known about severity from the trials

A review of the SURPASS trials describes adverse events overall as mostly mild to moderate and identifies nausea, diarrhea, decreased appetite and vomiting among the most common gastrointestinal events [2].

The label also reports that the majority of reports of nausea, vomiting and/or diarrhea occurred during dose escalation and decreased over time [1].

In the head-to-head diabetes trial SURPASS-2 — open-label, 40 weeks, 1,879 adults on metformin — nausea was reported in 17% to 22% of tirzepatide-treated patients across the 5, 10 and 15 mg doses, versus 18% with semaglutide 1 mg [3].

The label cautions that adverse reaction rates from trials of different drugs cannot be compared directly, because trials run under widely varying conditions and the rates may not reflect practice [1].

Where the label draws its own lines

The label does not define a nausea severity scale, but it does describe warnings that can involve nausea.

Volume depletion and kidney injury. The label describes postmarketing reports of acute kidney injury, in some cases requiring hemodialysis, and states that most occurred in patients who had gastrointestinal reactions leading to dehydration such as nausea, vomiting or diarrhea. It states that renal function should be monitored in patients reporting reactions that could lead to volume depletion, especially during initiation and dose escalation [1].

Pancreatitis. The label states that patients should be observed after starting Mounjaro for signs of acute pancreatitis, which may include persistent or severe abdominal pain sometimes radiating to the back, and which may or may not be accompanied by nausea or vomiting. If pancreatitis is suspected, the label says to discontinue Mounjaro [1].

Gastroparesis. Mounjaro is not recommended in patients with severe gastroparesis [1].

Does the nausea effect fade?

The label states that tirzepatide delays gastric emptying and that this delay is largest after the first dose and diminishes over time [1]. It also states that most nausea, vomiting and diarrhea reports came during dose escalation and decreased over time [1].

On oral drug absorption, the label reports that after a first 5 mg dose acetaminophen reached a lower peak concentration and peaked 1 hour later, while by week 6 on 15 mg there was no meaningful effect on its peak concentration or peak time [1].

The label's dose steps: the starting dose is 2.5 mg once weekly, with increases of 2.5 mg only after at least 4 weeks on the current dose and only if more glycemic control is needed, to a maximum of 15 mg weekly in adults [1].

What is not established

We found no trial that tested an antiemetic alongside tirzepatide. Reports submitted to the FDA's adverse event system do not settle it: the agency states that these reports cannot be used to estimate how often an event occurs and that a report does not establish that the drug caused it [4].