From the FDA Drug Label
Octreotide acetate injection is indicated to reduce blood levels of growth hormone (GH) and insulin growth factor-1 (IGF-1; somatomedin C) in acromegaly patients who have had inadequate response to or cannot be treated with surgical resection, pituitary irradiation, and bromocriptine mesylate at maximally tolerated doses Octreotide acetate injection is indicated for the symptomatic treatment of patients with metastatic carcinoid tumors where it suppresses or inhibits the severe diarrhea and flushing episodes associated with the disease. Octreotide acetate injection is indicated for the treatment of the profuse watery diarrhea associated with VIP-secreting tumors.
The indications for ocreotide are:
- Acromegaly: to reduce blood levels of growth hormone (GH) and insulin growth factor-1 (IGF-1; somatomedin C)
- Carcinoid Tumors: for the symptomatic treatment of patients with metastatic carcinoid tumors
- Vasoactive Intestinal Peptide Tumors (VIPomas): for the treatment of the profuse watery diarrhea associated with VIP-secreting tumors. The mechanism of action (MoA) is:
- Inhibition of growth hormone (GH), glucagon, and insulin
- Suppression of luteinizing hormone (LH) response to gonadotropin releasing hormone (GnRH)
- Decrease of splanchnic blood flow
- Inhibition of release of serotonin, gastrin, vasoactive intestinal peptide (VIP), secretin, motilin, and pancreatic polypeptide The effects are:
- Reduction of GH and IGF-1 levels in patients with acromegaly
- Suppression of severe diarrhea and flushing episodes in patients with metastatic carcinoid tumors
- Treatment of profuse watery diarrhea associated with VIP-secreting tumors Contraindications are not explicitly stated in the provided drug labels 1 1.
From the Research
Octreotide is a synthetic somatostatin analog primarily used to treat acromegaly, carcinoid syndrome, VIPomas, and other neuroendocrine tumors, with its mechanism of action involving the inhibition of hormone secretion through binding to somatostatin receptors, particularly SSTR2 and SSTR5, as supported by the most recent study 2.
Indications for Octreotide
- Acromegaly: to reduce growth hormone and insulin-like growth factor 1 (IGF-1) levels, as discussed in 3 and 2
- Carcinoid syndrome: to control flushing and diarrhea, as mentioned in the general use of somatostatin analogues 3
- VIPomas and other neuroendocrine tumors: to manage secretory diarrhea and other symptoms of hormone hypersecretion, as part of the broader application of somatostatin analogues in neuroendocrine tumors 3
- Variceal bleeding: to decrease splanchnic blood flow, as part of the management of acute bleeding episodes
- Secretory diarrhea and dumping syndrome: to reduce gastrointestinal secretions and improve symptoms, as supported by the mechanism of action of octreotide
Mechanism of Action and Effects
Octreotide works by binding to somatostatin receptors, primarily SSTR2 and SSTR5, which inhibits the secretion of various hormones including growth hormone, insulin, glucagon, and gut peptides. This leads to:
- Suppression of tumor growth in neuroendocrine tumors
- Reduction in diarrhea in conditions like VIPomas and secretory diarrhea
- Control of flushing in carcinoid syndrome
- Management of hypoglycemia in certain conditions
- Decrease in splanchnic blood flow, which is beneficial in variceal bleeding
Contraindications and Precautions
- Contraindicated in patients with hypersensitivity to octreotide or its components, as with any medication
- Caution is warranted in patients with:
- Gallbladder disease, as octreotide may cause cholelithiasis
- Diabetes, due to its effects on glucose metabolism
- Cardiac conduction abnormalities
- Renal or hepatic impairment, as the drug's metabolism and excretion may be affected
Side Effects
- Injection site pain
- Gastrointestinal disturbances
- Hyperglycemia or hypoglycemia
- QT prolongation with long-term use, as reported in various studies including 2
Dosing
Dosing varies by indication, typically starting at 50-100 mcg subcutaneously 2-3 times daily for acute conditions, with long-acting formulations available for chronic management, as discussed in the context of acromegaly treatment 4 and 2. The most recent study 2 supports the use of oral octreotide capsules as an alternative to injectable formulations for the treatment of acromegaly, offering improved patient-reported quality of life measures.