Octreotide
Octreotide (Sandostatin)
Octreotide is a synthetic octapeptide analog of somatostatin with a significantly longer half-life, used clinically to treat acromegaly, carcinoid tumors, VIPomas, and variceal bleeding. It suppresses the secretion of growth hormone, glucagon, insulin, and various gastrointestinal hormones, making it essential in managing hormone-secreting tumors and portal hypertension.
Mechanism of Action
Octreotide binds primarily to somatostatin receptors SSTR2 and SSTR5 on target cells, activating inhibitory G-proteins (Gi) that reduce intracellular cAMP and suppress hormone secretion. This results in decreased GH release from the pituitary, inhibition of glucagon and insulin from the pancreas, and reduced splanchnic blood flow via vasoconstriction of mesenteric vasculature. It also inhibits gastrointestinal motility and secretion by acting on enteric somatostatin receptors.
Evidence by Health Goal(18 goals)
Dosing Protocols
Subcutaneous injection; administered between meals and at bedtime to reduce GI side effects
Starting dose is typically 50mcg subcutaneously 2-3x daily, titrated upward based on response and tolerability. For acromegaly, doses up to 1500mcg/day may be used. Long-acting depot formulations (Sandostatin LAR) dosed at 10-40mg IM once monthly are preferred for chronic management. IV infusion used acutely for variceal bleeding at 25-50mcg/hr.
Safety & Side Effects
Octreotide has a well-characterized safety profile in clinical use but requires medical supervision due to its effects on glucose regulation, cardiac conduction, and gallbladder function; long-term use necessitates periodic monitoring of thyroid function, blood glucose, gallbladder ultrasound, and cardiac status. It is a prescription-only medication in all major jurisdictions and should never be used without physician oversight, particularly in diabetic patients or those with cardiac disease.
Possible Side Effects
- !Gastrointestinal disturbances including nausea, diarrhea, abdominal cramping, and flatulence (most common, especially early in treatment)
- !Cholelithiasis (gallstone formation) with prolonged use due to reduced gallbladder motility and bile acid secretion
- !Injection site pain, redness, and induration with subcutaneous administration
- !Hypoglycemia or hyperglycemia due to imbalanced suppression of insulin and glucagon
- !Bradycardia and cardiac conduction abnormalities including QT prolongation
- !Hypothyroidism with long-term use due to suppression of TSH
- !Steatorrhea and fat malabsorption from reduced pancreatic enzyme secretion
- !Headache and dizziness
Interactions
- -Cyclosporine: Octreotide reduces cyclosporine absorption, potentially leading to subtherapeutic immunosuppressant levels and transplant rejection risk
- -Antidiabetic medications (insulin, sulfonylureas): Unpredictable alterations in blood glucose due to simultaneous suppression of both insulin and glucagon; dose adjustments required
- -Beta-blockers and calcium channel blockers: Additive bradycardia risk; use caution and monitor heart rate and conduction
- -QT-prolonging drugs (antiarrhythmics, antipsychotics): Increased risk of QT prolongation and potentially fatal arrhythmias
- -Bromocriptine: Octreotide may increase bioavailability of bromocriptine, enhancing its dopaminergic effects
Cost & Where to Buy
Prescription-only; cost varies enormously based on formulation (immediate-release vials vs. LAR depot), insurance coverage, and country. Generic octreotide acetate vials are significantly cheaper than branded Sandostatin. LAR depot injections can exceed $3000/month without insurance. Research-grade octreotide from peptide vendors ranges $80-200/month but is not approved for human use.
Search on Amazon