Pharm 101: Octreotide

Class

Somatostatin analogue

Pharmacodynamics
  • Long-acting somatostatin analogue
  • Reduces splanchnic blood flow and portal venous pressure by unknown mechanisms (hence reduces variceal pressures)
  • Inhibits endocrine and paracrine factor secretion, including insulin, glucagon, gastrin, GH and TSH
  • 45 times more potent than somatostatin at inhibiting GH, but only twice as potent in reducing insulin secretion
    • Hyperglycaemia therefore rarely occurs
Pharmacokinetics
  • IV, IM, SC administration
  • Half-life 80 minutes
  • Hepatic metabolism (30-40%)
  • 20% excreted unchanged by kidney
Clinical uses
  • Acute variceal bleeding:
    • IV 50mcg bolus then 50mcg/hour infusion
    • Infusion is required because of short half-life
  • Sulphonylurea overdose
  • Reduction of symptoms of hormone secreting tumours e.g. pituitary and carcinoid tumours (long-acting injections)
Adverse effects
  • GI upset
  • Biliary: gallstones in 25% after 6 months (annual incidence of symptomatic gallstones 1%)
  • CVS: sinus bradycardia 25%, conduction disturbances 10%
  • Pain at site of injection
  • B12 deficiency with long-term use
Further reading
References
Pharm 101 700

Pharmacology 101

Top 200 drugs

MBBS CCPU (RCE, Biliary, DVT, E-FAST, AAA) Rob is an Emergency Medicine Advanced Trainee based in Melbourne, Australia. He has special interests in medical education, ECG interpretation, and the use of diagnostic and procedural ultrasound in the undifferentiated and unwell patient.

Follow him on twitter: @rob_buttner | ECG Library |

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.