Octreotide 83150-76-9

Pharmacological effects

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.
• 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.

Adverse effects

Most frequent: abdominal pain with cramps, bradycardia, cardiac conduction changes, gastrointestinal reactions (including nausea/vomiting and diarrhea or constipation) and injection site reactions. Less frequent: discolored feces, dyspepsia, flatulence, hypothyroidism, steatorrhea, tenesmusRare: acute pancreatitis, alopecia, biliary calculi, liver failure, dizziness, edema, fatigue, fever, flushing, generalized weakness, headache, hepatitis, hyperbilirubinemia, hyperglycemia, prolonged QT interval

Uses

The Food and Drug Administration (FDA) has approved the usage of a salt form of this peptide, octreotide acetate, as an injectable depot formulation for the treatment of acromegaly, the treatment of diarrhea and flushing episodes associated with carcinoid syndrome, and treatment of diarrhea in patients with vasoactive intestinal peptide-secreting tumors (VIPomas). Octreotide has also been used off-label for the treatment of severe, refractory diarrhea from other causes. It is used in toxicology for the treatment of prolonged recurrent hypoglycemia after sulfonylurea and possibly meglitinides overdose. Octreotide has also been used with varying degrees of success in infants with nesidioblastosis to help decrease insulin hypersecretion. In patients with suspected esophageal varices, octreotide can be given to help decrease bleeding. Octreotide has been investigated for patients with pain from chronic pancreatitis. Octreotide may be useful in the treatment of thymic neoplasms. Octreotide has been used as an unlicensed drug, injected sub-cutaneously in the management of hypertrophic pulmonary osteoarthropathy (HPOA), secondary to non-small cell lung carcinoma. Although its mechanism is not known it appears to reduce the pain associated with HPOAIt has been used in the treatment of malignant bowel obstruction. Octreotide may be used in conjunction with midodrine to partially reverse peripheral vasodilation in the hepato-renal syndrome. By increasing systemic vascular resistance, these drugs reduce shunting and improve renal perfusion, prolonging survival until definitive treatment with liver transplant. In recent years, the drug has been shown to be effective in the treatment of chylothorax.