Debut of a somatostatin analog: octreotide in review.

Octreotide is a long-acting cyclic octapeptide with pharmacologic actions mimicking those of the natural hormone somatostatin. It can suppress the secretion of serotonin, as well as the gastroenteropancreatic peptides gastrin, vasoactive intestinal peptide (VIP), insulin, glucagon, secretin, motilin, and pancreatic polypeptide. It also suppresses growth hormone and decreases splanchnic blood flow. Octreotide is completely and rapidly absorbed following subcutaneous injection and has an elimination half-life of 1.5 hours. Clinical trials reviewed here show octreotide useful in the treatment of diarrhea associated with VIP secreting tumors, as well as diarrhea and flushing associated with carcinoid syndrome, both conditions for which the drug is approved. Clinical trials involving the use of octreotide in the treatment of acromegaly are also reviewed. Adverse reactions to octreotide are mild to moderate and most commonly involve injection site pain and diarrhea. Drug interactions are apparently related to the drug's pharmacologic effects. Octreotide is given subcutaneously two to three times daily, with daily doses ranging from 50mcg to 1,500mcg per day. Further research appears necessary to clarify dosing issues.