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. 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 (thyrotropinoma), 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.
Pharmacology
Since octreotide resembles somatostatin in physiological activities, it can:

inhibit secretion of many hormones, such as gastrin, cholecystokinin, glucagon, growth hormone, insulin, secretin, pancreatic polypeptide, TSH, and vasoactive intestinal peptide,
reduce secretion of fluids by the intestine and pancreas,
reduce gastrointestinal motility and inhibit contraction of the gallbladder,
inhibit the action of certain hormones from the anterior pituitary,
cause vasoconstriction in the blood vessels, and
reduce portal vessel pressures in bleeding varices.It has also been shown to produce analgesic effects, most probably acting as a partial agonist at the mu opioid receptor. Pharmacokinetics
Octreotide is absorbed quickly and completely after subcutaneous application. Maximal plasma concentration is reached after 30 minutes. The elimination half-life is 100 minutes (1.7 hours) on average when applied subcutaneously; after intravenous injection, the substance is eliminated in two phases with half-lives of 10 and 90 minutes, respectively.