Sincalide

Sincalide (Kinevac) is a real, FDA-approved synthetic fragment of cholecystokinin (CCK), used purely as a diagnostic tool to provoke gallbladder contraction during imaging studies for suspected biliary dyskinesia.

What it is

Sincalide is a synthetic C-terminal octapeptide — the last 8 amino acids — of the 33-amino-acid hormone cholecystokinin (CCK), a fragment that retains the full biological activity of the natural hormone. It binds and stimulates the CCK-A (CCK1) receptor, the same receptor natural CCK acts on to trigger gallbladder contraction and pancreatic enzyme secretion after eating.

How the diagnostic test works

Sincalide's main clinical use is cholescintigraphy (the "HIDA scan"): after a radioactive tracer is taken up by the gallbladder, sincalide is given to provoke contraction, and the resulting gallbladder ejection fraction (GBEF) is calculated from how much tracer is expelled. A low GBEF supports a diagnosis of chronic acalculous gallbladder disease or biliary dyskinesia — a real, functional gallbladder problem that doesn't show up as gallstones on standard imaging. Sincalide is also sometimes used to clear a falsely non-visualized gallbladder before tracer administration, and — often paired historically with secretin — to stimulate pancreatic enzyme secretion for pancreatic function testing.

Current status

Brand Kinevac (Bracco Diagnostics) remains marketed, manufactured/distributed by Fresenius Kabi, which also launched an authorized generic ("Sincalide for Injection") in June 2023. This diagnostic-imaging agent has had intermittent supply shortages historically, worth checking current availability if you need it. No grey-market or wellness-market presence.