Octreotide (Sandostatin)

Benefits

About Octreotide (Sandostatin)

Octreotide is a synthetic octapeptide analog of natural somatostatin, first approved by the FDA in 1988 for the treatment of acromegaly. It mimics the hormone somatostatin but with a dramatically longer half-life — about 1.7 to 1.9 hours compared to 1-3 minutes for native somatostatin — making it practical for clinical use. The drug works primarily by binding to somatostatin receptor subtypes 2 and 5 (SST2 and SST5), suppressing the release of growth hormone, insulin, glucagon, and multiple gastrointestinal hormones. Octreotide carries three FDA-approved indications: acromegaly (reducing growth hormone and IGF-1 levels when surgery or radiation hasn't achieved adequate control), carcinoid syndrome (managing severe diarrhea and flushing episodes from metastatic carcinoid tumors), and VIPomas (controlling profuse watery diarrhea caused by vasoactive intestinal peptide-secreting tumors). The landmark PROMID trial also demonstrated its antiproliferative effects in neuroendocrine tumors, and it's now approved in over 40 countries for tumor growth control in well-differentiated midgut NETs. Two formulations are available: Sandostatin Injection for subcutaneous or IV use (dosed 2-3 times daily), and Sandostatin LAR Depot for monthly intramuscular injection. The short-acting form offers near-complete bioavailability (~100% SC) with peak plasma levels at about 0.4 hours. The LAR formulation uses microsphere technology to release octreotide gradually over 4 weeks, with ~60% bioavailability relative to the SC form. While generally well tolerated, the most common limitation is gallstone formation — occurring in 25-65% of long-term users — due to the drug's suppression of gallbladder contractility and bile secretion. Blood glucose abnormalities (both hyper- and hypoglycemia) also require monitoring, as octreotide suppresses both insulin and glucagon. Octreotide has been in clinical use for over 35 years with an extensive safety and efficacy database.

Who Should Consider Octreotide (Sandostatin)

• Patients with acromegaly not adequately controlled by surgery or radiation
• Individuals with metastatic carcinoid tumors experiencing flushing and diarrhea
• Patients with VIP-secreting tumors and profuse watery diarrhea
• Adults with well-differentiated neuroendocrine tumors requiring growth control
• Patients with thyrotroph adenomas secreting excess TSH
• Individuals with refractory diarrhea from short bowel syndrome or AIDS (off-label)

How Octreotide (Sandostatin) Works

Octreotide is a synthetic octapeptide that mimics endogenous somatostatin by binding to G protein-coupled somatostatin receptors (SSTRs), with highest affinity for SSTR2 (subnanomolar) and moderate affinity for SSTR3 and SSTR5. Upon binding, it activates inhibitory G proteins (Gi/Go), which suppress adenylyl cyclase activity and reduce intracellular cAMP levels. This triggers multiple downstream effects: inhibition of hormone secretion from pituitary somatotrophs (reducing GH release), suppression of pancreatic endocrine cells (decreasing insulin and glucagon output), and reduction of gastrointestinal hormone release including VIP, gastrin, secretin, and motilin. At the molecular level, octreotide binding causes rearrangement of a hydrophobic lock between transmembrane helices TM3 and TM6, enabling Galphai protein engagement. This is followed by GRK2/3-mediated phosphorylation of threonine residues in the receptor's C-terminal TTETQRT motif, triggering beta-arrestin recruitment and receptor internalization. Beyond hormone suppression, octreotide exerts antiproliferative effects through SSTR2-mediated pathways: it upregulates the cell cycle inhibitor p27, downregulates cyclin D1, and can induce apoptosis in somatotroph tumor cells. These combined antisecretory and antiproliferative actions underlie its clinical efficacy in both hormone-excess states and neuroendocrine tumor growth control.

What to Expect

Dosing Protocol

Note: Octreotide is an FDA-approved synthetic somatostatin analog available in two formulations: Sandostatin (short-acting subcutaneous injection, dosed 2-3 times daily) and Sandostatin LAR Depot (long-acting intramuscular injection, dosed every 28 days at 10-30 mg). Supplied as a pre-filled solution — no reconstitution with bacteriostatic water is needed. Dosing in the calculator reflects subcutaneous Sandostatin Injection in mcg. For the LAR depot formulation, doses range from 10-30 mg IM every 4 weeks and must be administered by a healthcare provider. Dose adjustments are needed in patients with hepatic cirrhosis. This is a prescription medication and should only be used under medical supervision.

How to Inject Octreotide (Sandostatin)

Sandostatin Injection: Administer subcutaneously in the abdomen or thigh, rotating injection sites. Typical starting dose for acromegaly is 50 mcg SC three times daily, titrated up to 100-200 mcg three times daily based on GH/IGF-1 response. For carcinoid syndrome, start at 100-600 mcg/day in 2-4 divided doses. Allow the solution to reach room temperature before injection to reduce discomfort. For Sandostatin LAR Depot: administered by a healthcare provider as a deep intraglutal IM injection every 28 days at 20 mg, adjustable to 10-30 mg based on response. Overlap with SC injections for 2 weeks when initiating LAR. Never inject LAR intravenously or subcutaneously. IV administration of short-acting octreotide should be diluted in 50-200 mL normal saline and infused over 15-30 minutes.

Cycling Protocol

Pharmacokinetics

Side Effects

The most common side effects are gastrointestinal: diarrhea, nausea, abdominal pain, and flatulence (reported in 34-61% of patients). Gallstone formation is a significant long-term concern, occurring in 25-65% of acromegaly patients on maintenance therapy due to suppressed gallbladder motility and bile secretion. Bradycardia occurs in about 25% of patients. Blood sugar disturbances are common — octreotide suppresses both insulin and glucagon, leading to hyperglycemia (16%) or, less frequently, hypoglycemia. Injection site pain affects approximately 7.7% of users. Hypothyroidism has been reported with long-term use. Cardiac conduction abnormalities including QT prolongation warrant monitoring, especially in patients taking other QT-prolonging medications. Less common effects include steatorrhea, hair loss, and vitamin B12 deficiency with prolonged use.

Contraindications

Drug Interactions

Storage & Stability

Molecular Profile

Related Peptides

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Tesamorelin

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HGH (Somatropin)

Growth Hormone

Sermorelin

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References

1. Clinical pharmacokinetics of octreotide. Therapeutic applications in patients with pituitary tumoursPubMed 8287633
2. Octreotide treatment of acromegaly. A randomized, multicenter studyPubMed 1416572
3. Primary treatment of acromegaly with octreotide LAR: a long-term (up to nine years) prospective studyPubMed 16449332
4. PROMID: Placebo-controlled study on octreotide LAR in metastatic neuroendocrine midgut tumorsPubMed 19704057
5. Octreotide-associated biliary tract dysfunction and gallstone formationPubMed 7611194
6. Sandostatin (octreotide acetate) Injection — FDA Prescribing InformationFDA Label