Octreotide

INTRODUCTION:
  • Octreotide 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.
MECHANISM OF ACTION:
  • Its mechanism of action appears to involve inhibition of hormone secretion, including 5-HT and various other GI peptides (e.g., gastrin, vasoactive intestinal polypeptide (VIP), insulin, secretin, etc.).
ACTION:
  • 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
INDICATION:
  • Palliative management of gastrointestinal endocrine tumors, such as:
  1. Carcinoid tumors to suppress or inhibit the associated severe diarrhea and facial flushing
  • Vasoactive intestinal polypeptide-secreting tumors (VlPomas) For the treatment of the profuse watery diarrhea associated with VlPomas.
  • Suppress secretion of growth hormone from pituitary tumors and decrease blood concentrations of insulin-like growth factor-I (IGF-I; somatomedin C) in patients with acromegaly Reduce the incidence and severity of the postoperative complications of high-risk pancreatic surgery. These complications may include abscess formation and subsequent sepsis, acute pancreatitis, pancreatic fistula, and peripancreatic fluid collection.
  • Varices, gastroesophageal, bleeding
  • Reverse life-threatening hypotension due to carcinoid crisis during induction of anesthesia.
  • Palliative treatment of the symptoms resulting from hyperinsulinemia from severe refractory metastatic insulinoma.
  • AIDS patients with severe secretory diarrhea who have failed to respond to antimicrobial or antimotility agents
CONTRAINDICATION:
  • Octreotide has not been adequately studied for the treatment of children and pregnant and lactating women.
  • The drug is given to these groups of patients only if a risk-benefit analysis is positive.
ADVERSE EFFECT:
  • Headache
  • Hypothyroidism
  • Cardiac conduction changes
  • Gastrointestinal reactions (including cramps, nausea/vomiting and diarrhoea or constipation),
  • Gallstones,
  • Reduction of insulin release,
  • Hyperglycemia or hypoglycemia, and (usually transient) injection site reactions.
  • Slow heart rate,
  • Skin reactions such as pruritus,
  • Hyperbilirubinemia,
  • Hypothyroidism,
  • Dizziness
  • Dyspnoea.
  • Rare side effects include
  1. Acute anaphylactic reactions, pancreatitis and hepatitis
  2. A prolonged QT interval
Exam Question
  • Drug of choice for diarrhea in AIDS is Octreotide
  • Octreotide is used in Insulinoma, Glucagonoma & Carcinoids
  • Octreotide is Useful for Acromegaly, variceal bleeding,secretory diarrhea & Suppresses growth Hormone secretion
  • Octreotide can be used in the management of acute pancreatitis
Don't Forget to Solve all the previous Year Question asked on Octreotide