Sandostatin
Sandostatin
Generic Name
Sandostatin
Brand Names
for octreotide, a synthetic somatostatin analog used to manage hormone‑secreting tumors and associated clinical syndromes.
Mechanism
- Somatostatin Receptor Agonist – Octreotide binds with high affinity to somatostatin receptors 2 and 5 (SSTR2/5), mimicking natural somatostatin.
- Inhibition of Hormone Secretion – Blocks β‑adrenergic‑mediated cAMP production, reducing secretion of growth hormone (GH), insulin, glucagon, gastrin, cholecystokinin, and vasoactive intestinal peptide (VIP).
- Anti‑angiogenic & Anti‑proliferative Effects – Inhibits VEGF and FGF, reducing tumor vascularity; promotes apoptosis in certain neuroendocrine tumors.
- Functional Outcomes – Decreases diarrhoea, flushing, and reduces tumor burden in acromegaly and carcinoid syndromes.
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Pharmacokinetics
| Parameter | Typical Value | Notes |
| Absorption | Subcutaneous: ~37 % bioavailability; Intramuscular: ~60 % | Bioavailability increases with slower injection rate. |
| Distribution | Volume of distribution ≈ 5 L | High protein binding (~90 %). |
| Metabolism | Hepatic proteolysis via peptidases | No major CYP450 involvement. |
| Elimination | Urinary excretion (≈ 10 % unchanged); renal clearance ≈ 10 mL/min | Half‑life: 2–3 h (SC); 2–4 h (IV). |
| Reformulation | Octreotide decanoate (Sandostatin LAR) releases over 4–8 weeks | Depot formulation for monthly dosing. |
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Indications
- Acromegaly – Adjunctive or pre‑operative therapy.
- Carcinoid syndrome – Control flushing, diarrhoea, and desmoplasia.
- VIPoma – Control secretory diarrhoea and electrolyte disturbances.
- Familial or sporadic carcinoids – Tumor size reduction and symptomatic relief.
- Gastrin‑secreting (Zollinger–Ellison) tumors – Manage refractory peptic ulcer disease.
- Pheochromocytoma – Temporary peri‑operative control of catecholamine release (rare).
- Reproductive disorders – Suppress precocious puberty (rare).
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Contraindications
- Contraindications
- Known hypersensitivity to octreotide or excipients.
- Severe renal impairment (CrCl < 30 mL/min); consider dose adjustment.
- Warnings
- Cholelithiasis – May precipitate gallstones; monitor patients with gallbladder disease.
- Glycemic disturbances – Can delay glucose uptake → hypoglycaemia (especially with insulin) or hyperglycaemia (via glucagon inhibition).
- Cardiovascular – Bradycardia, hypotension with rapid IV infusion.
- Pancreatitis – Rare; discontinue if symptoms develop.
- Ophthalmic – Ocular irritation possible (rare).
- Precautions
- Use with caution in pregnancy (category C).
- Monitor for injection site reactions; consider alternate sites or route.
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Dosing
- Acromegaly
- *IV/SC*: 10 µg/kg every 24 h or 100 µg thrice daily.
- *Depot (LAR)*: 20–30 mg intramuscularly every 4–8 weeks.
- Carcinoid Syndrome
- *SC*: 100 µg 3–4 times daily (adjust for GI symptoms).
- *Depot*: 20 mg monthly.
- VIPoma
- SC: 100 µg 3–4×/day titrated to symptom control.
- Zollinger–Ellison (Gastrinoma)
- SC: 100 µg 2–4×/day or LAR as maintenance.
- Administration Tips
- Rapid IV infusion (> 8 h) is recommended for acute situations.
- Subcutaneous injections: dissolve in 0.9 % saline, inject into abdomen or thigh, rotate sites.
- LAR: use a dedicated syringe with attached device; maintain drug integrity.
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Adverse Effects
Common
• Nausea, vomiting, abdominal pain, bloating.
• Injection site erythema, pain, induration.
• Hyperglycemia or hypoglycemia (dose‑dependent).
• Diarrhoea or constipation (rare).
Serious
• Cholelithiasis and gallbladder sludge.
• Acute pancreatitis (abdominal pain, elevated lipase).
• Bradycardia, QT prolongation.
• Severe hypersensitivity reactions (anaphylaxis).
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Monitoring
- Biochemical – Serum GH, IGF‑1; 24‑hr urinary 5‑HT‑P/EU.
- Metabolic – Blood glucose & HbA1c; electrolytes in VIPoma.
- Imaging – MRI/CT or PET‑CT for tumor size every 6–12 months.
- Liver & Renal – Serum creatinine, eGFR; liver function panels.
- Gallbladder Ultrasound – Baseline and annually in high‑risk patients.
- Cardiac – ECG if bradycardia or QT prolongation risk.
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Clinical Pearls
| Pearls | Rationale |
| Depot dosing for chronic disease – LAR provides steady plasma levels; reduces clinic visits, improves adherence. | |
| Rapid IV infusion to abort carcinoid crisis – Slow infusion over ≥ 8 h avoids severe bradycardia; if severe, start with 50 µg IV, titrate up. | |
| Switch to LAR when poor compliance – Monthly injections eliminate the need for daily SC dosing. | |
| Check HbA1c at baseline then every 3 months in diabetics – Octreotide can worsen hyperglycemia, requiring insulin or sulfonylurea adjustments. | |
| Contrast‑induced cholecystitis – Patients with gallstones should avoid prolonged fasting; consider ursodeoxycholic acid prophylaxis if indicated. | |
| Use 30‑mL syringe for LAR – The dedicated injection device requires a 30‑mL syringe; avoid smaller syringes to prevent mis‑dosing. | |
| Avoid concurrent high‑dose steroids – Prednisone can blunt ghrelin suppression; re‑evaluate dosing during co‑therapy. | |
| Manage injection‑site pain with topical lidocaine – Decreases patient discomfort and improves tolerability. | |
| Use octreotide in acute diabetic ketoacidosis – Suppression of insulin may exacerbate DKA; monitor closely if used off‑label. | |
| Reversibility – In case of severe GI toxicity, octreotide can be stopped; symptoms resolve within 24 h. |
> Bottom line: Octreotide (Sandostatin) remains the cornerstone for controlling hormonally driven tumors and their systemic manifestations. Proper dosing, vigilant monitoring, and proactive management of known adverse effects maximize therapeutic benefit while safeguarding patient safety.