What is octreotide used for?

Uses of Octreotide in Clinical Practice

Octreotide is primarily used for the management of neuroendocrine tumors (NETs), particularly for symptom control in carcinoid syndrome, VIPomas, and as an antiproliferative agent for certain NETs. 1

Primary Indications

1. Neuroendocrine Tumors

• Carcinoid Syndrome: Controls symptoms of flushing and diarrhea in patients with carcinoid tumors 1

  • Standard doses: 20-30 mg intramuscularly every 4 weeks (long-acting release formulation)
  • Short-acting formulation (150-250 mcg subcutaneously three times daily) can be added for breakthrough symptoms 1

• VIPomas (Vasoactive Intestinal Peptide-secreting tumors): Manages watery diarrhea associated with VIP-secreting tumors 1

  • Particularly effective for the WDHA syndrome (Watery Diarrhea, Hypokalemia, Achlorhydria)

• Tumor Growth Control: Inhibits tumor growth in patients with metastatic midgut NETs 1

  • The PROMID study demonstrated significantly longer time to tumor progression with octreotide LAR compared to placebo (14.3 vs. 6.0 months) 1

2. Prevention of Carcinoid Crisis

• Administered before, during, and after procedures (surgery, hepatic artery embolization) to prevent carcinoid crisis in patients with carcinoid tumors 1
  • Recommended as intravenous administration (50 mcg/h) starting 12 hours before the procedure and continuing 48 hours after 1

3. Other Endocrine Conditions

• Acromegaly: Controls growth hormone and IGF-1 levels 2, 3
• Thyrotropinomas: Inhibits thyroid-stimulating hormone secretion 4

Mechanism of Action

Octreotide is a somatostatin analog that:

• Binds primarily to somatostatin receptor subtypes 2 and 5 1
• Inhibits secretion of various hormones including:
  • Serotonin
  • Gastrin
  • Vasoactive intestinal peptide (VIP)
  • Growth hormone
  • Insulin and glucagon
  • Other peptides of the gastroenteropancreatic system 5, 6
• Decreases splanchnic blood flow 5

Administration

• Short-acting formulation: 50-100 mcg subcutaneously 2-3 times daily, up to 1500 mcg/day 1
• Long-acting formulations:
  • Octreotide LAR: 10-30 mg intramuscularly every 4 weeks
  • Lanreotide Autogel: 60-120 mg every 4 weeks 1

Special Considerations

• Insulinomas: Use with extreme caution as it may worsen hypoglycemia in some patients 7

  • Should only be used in insulinoma patients with positive somatostatin receptor scans

• Imaging Considerations: For optimal somatostatin receptor imaging, short-acting somatostatin analogs should be withdrawn 24-48 hours before imaging; long-acting formulations should be scheduled toward the end of the dosing interval 1

• Gastrinomas: Not considered first-line therapy; proton pump inhibitors are preferred 1

Side Effects

• Gastrointestinal symptoms: Abdominal pain, diarrhea, nausea, bloating (usually transient) 4
• Gallbladder abnormalities: Sediment, sludge, gallstones (in long-term therapy) 2, 3
• Glucose metabolism alterations: Both hypo- and hyperglycemia 1, 3
• Injection site pain 8
• Fat malabsorption and vitamin A and D malabsorption 1

Octreotide has transformed the management of functional neuroendocrine tumors, providing effective symptom control and improved quality of life for patients with previously difficult-to-manage conditions.