Octreotide, sold under the brand name Sandostatin among others, is an octapeptide that mimics natural somatostatin pharmacologically, though it is a more potent inhibitor of growth hormone, glucagon, and insulin than the natural hormone. It was first synthesized in 1979 by the chemist Wilfried Bauer, and binds predominantly to the somatostatin receptors SSTR2 and SSTR5. It was approved for use in the United States in 1988. Octreotide (Mycapssa) was approved for medical use in the European Union in 2022. , octreotide (Mycapssa) is the first and only oral somatostatin analog (SSA) approved by the FDA. Medical uses Tumors Octreotide is used for the treatment of growth hormone producing tumors (acromegaly and gigantism), when surgery is contraindicated, pituitary tumors that secrete thyroid-stimulating hormone (thyrotropinomata), diarrhea and flushing episodes associated with carcinoid syndrome, and diarrhea in people with vasoactive intestinal peptide-secreting tumors (VIPomas). Octreotide is also used in mild cases of glucagonoma when surgery is not an option. Bleeding esophageal varices Octreotide is often given as an infusion for management of acute hemorrhage from esophageal varices in liver cirrhosis on the basis that it reduces portal venous pressure, though current evidence suggests that this effect is transient and does not improve survival. Radiolabeling Octreotide is used in nuclear medicine imaging by labeling with indium-111 (Octreoscan) to noninvasively image neuroendocrine and other tumours expressing somatostatin receptors. More recently, it has been radiolabeled with carbon-11 as well as gallium-68 (using edotreotide), enabling imaging with positron emission tomography (PET), which provides higher resolution and sensitivity. Octreotide (usually as the derivative edotreotide or DOTATOC) can also be labeled with a variety of therapeutic radionuclides, such as yttrium-90 or lutetium-177, to enable peptide receptor radionuclide therapy (PRRT) for the treatment of unresectable neuroendocrine tumours. Acromegaly Octreotide can also be used in the treatment of acromegaly, a disorder of excessive growth hormone (GH). Octreotide, being a somatostatin analog, inhibits the release of GH from the pituitary gland through a process normally involved in negative feedback. In June 2020, Mycapssa (octreotide) was approved for medical use in the United States with an indication for the long-term maintenance treatment in acromegaly patients who have responded to and tolerated treatment with octreotide or lanreotide. Mycapssa is the first and only oral somatostatin analog (SSA) approved by the FDA. Gastrointestinal fistulae Octreotide helps in management of the fistula by reducing gastrointestinal secretions and inhibiting gastrointestinal motility, thus controlling and reducing its output.