Octreotide is a synthetic 8-amino-acid cyclic peptide (MW ~1019.2 g/mol) that mimics the pharmacological actions of natural somatostatin but with a significantly longer half-life. It was the first somatostatin analog approved by the FDA (1988) and is available as both an immediate-release subcutaneous injection (Sandostatin) and a long-acting intramuscular depot formulation (Sandostatin LAR). Octreotide is FDA-approved for acromegaly, severe diarrhea associated with carcinoid tumors, and VIPomas (vasoactive intestinal peptide-secreting tumors).
Category: Endocrine / Somatostatin Analog. Evidence rating: A (strong human clinical data).
Clinical status: FDA-approved (Sandostatin 1988; Sandostatin LAR 1998)
Octreotide binds preferentially to somatostatin receptor subtypes 2 (SSTR2) and 5 (SSTR5), with moderate affinity for SSTR3. It inhibits growth hormone, glucagon, and insulin secretion, reduces splanchnic blood flow, and suppresses secretion of serotonin, gastrin, vasoactive intestinal peptide,…
Safety considerations: Common (10-30%): nausea, abdominal pain/cramping, diarrhea, flatulence, constipation; Gallbladder abnormalities: cholelithiasis in 15-30% with long-term use; cholecystitis, biliary sludge; Glucose metabolism alterations: hyperglycemia or hypoglycemia depending on baseline hormonal status; monitor blood glucose.
Reviewed by the PeptideAtlas Editorial Team.
| Amino-acid sequence | D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Thr(ol) (disulfide bridge Cys2-Cys7) |
|---|---|
| Molecular weight | ~1019.2 g/mol |
| CAS number | 83150-76-9 |
| Half-life | ~1.5-2 hours (SC immediate-release); ~28 days effective duration (LAR) |
| Bioavailability | ~100% subcutaneous |
| Production method | synthetic |
| Anti-doping status | not-listed |
| US regulatory status | FDA-approved. Sandostatin (immediate-release SC) approved 1988 for acromegaly, carcinoid, VIPomas. Sandostatin LAR (long-acting IM depot) approved 1998. Multiple generics available. |
Related peptides: Lanreotide, Pasireotide, Somatostatin.
Compare: Octreotide vs Pasireotide.
Sandostatin is an immediate-release subcutaneous injection given 2-3 times daily, used for acute symptom control. Sandostatin LAR is a long-acting depot formulation injected intramuscularly once every 4 weeks, designed for chronic maintenance therapy. Patients are typically titrated on subcutaneous octreotide first, then transitioned to LAR.
The PROMID trial showed octreotide LAR significantly delayed tumor progression in midgut NETs. Tumor shrinkage (partial response) is uncommon, occurring in only about 3-5% of patients, but stable disease is achieved in a majority. Octreotide is primarily antiproliferative rather than cytoreductive.
Octreotide inhibits gallbladder motility and reduces bile secretion, leading to bile stasis and gallstone formation in 15-30% of patients on long-term therapy. Routine ultrasound monitoring of the gallbladder is recommended.
Both are somatostatin analogs with similar receptor binding profiles (SSTR2 and SSTR5). The main differences are practical: octreotide LAR requires healthcare-administered intramuscular injection after reconstitution, while lanreotide Autogel comes in a pre-filled syringe for deep subcutaneous injection that can be self-administered. Efficacy for acromegaly and NETs is broadly comparable. The…
Yes. Although not an FDA-approved indication, octreotide is widely used off-label for acute variceal hemorrhage in cirrhosis. It reduces splanchnic blood flow and portal venous pressure. Major society guidelines (AASLD, EASL) recommend octreotide IV infusion (50 mcg bolus followed by 50 mcg/hour for up to 5 days) as adjunctive therapy alongside endoscopic intervention.
Coverage on this site: Peptide Targeting Agents for In Vivo Tumor Imaging: A Practical Primer, Peptide-Receptor Systems for Tumor Imaging: A Field Guide, Representative Peptides for In Vivo Tumor Imaging, Macrocyclic Peptide Drugs: Structures, Pipelines and Oral Prospects.