The Wegovy label includes a specific warning about acute kidney injury. The warning is tied to severe GI reactions (vomiting, diarrhea) and the loss of body fluid that follows them.

Severe nausea drops fluid intake; severe diarrhea increases fluid loss; the kidneys respond to the resulting drop in blood volume. The peptide itself isn't toxic to kidney tissue. The chain is GI side effects → dehydration → kidney stress.

People with pre-existing kidney disease have less margin in that cascade, which is why the label flags them specifically. Closer monitoring during the first weeks on the peptide is what the label points to.