Recommended Dosage of Octreotide for Carcinoid Tumors and Acromegaly
For carcinoid tumors, the standard dosage of octreotide LAR is 20-30 mg intramuscularly every 4 weeks, while for acromegaly, the recommended initial dosage is 50 mcg subcutaneously three times daily, with maintenance doses ranging from 100-500 mcg three times daily. 1, 2
Dosing for Carcinoid Tumors
Initial Therapy
- Start with subcutaneous (SC) octreotide at 100-600 mcg daily in 2-4 divided doses during the first 2 weeks of therapy (mean daily dosage is 300 mcg) 2, 1
- For long-term management, transition to octreotide LAR 20-30 mg intramuscularly every 4 weeks 1
- During the first 2 weeks of LAR therapy, continue short-acting octreotide for symptom control until therapeutic levels of LAR are achieved 3
Dose Adjustments
- Dose and frequency may be increased for symptom control as needed 1
- Clinical benefit has been observed with doses as low as 50 mcg, while others required up to 1500 mcg/day, though experience with doses above 750 mcg/day is limited 2
- For patients with refractory symptoms, above-label doses (40-60 mg every 4 weeks or 30 mg every 3 weeks) have shown benefit in controlling diarrhea (62% improvement) and flushing (56% improvement) 4
Monitoring
- Monitor urinary 5-hydroxyindoleacetic acid (5-HIAA), plasma serotonin, and plasma Substance P to evaluate therapeutic response 2
- Consider cardiology consultation and echocardiogram to assess for carcinoid heart disease in patients with signs/symptoms of heart disease or before major surgery 1
Dosing for Acromegaly
Initial Therapy
- Begin with 50 mcg subcutaneously three times daily during the first 2 weeks of therapy 2
Maintenance Therapy
- The most common maintenance dosage is 100 mcg three times daily 2
- Dose may be increased up to 500 mcg three times daily based on growth hormone (GH) and insulin-like growth factor 1 (IGF-1) levels 2
- Doses greater than 300 mcg/day seldom provide additional biochemical benefit 2
Monitoring and Adjustments
- Monitor GH and IGF-1 levels every two weeks after initiating therapy or with dosage changes 2
- Target GH levels less than 5 ng/mL or IGF-1 levels within normal range 2
- Withdraw octreotide yearly for approximately 4 weeks in patients who have received pituitary irradiation to assess disease activity 2
Special Considerations
Breakthrough Symptoms
- For breakthrough symptoms in carcinoid syndrome, add short-acting octreotide (150-250 mcg subcutaneously three times daily) 1
Procedure Prophylaxis
- For patients with carcinoid syndrome undergoing procedures (surgery, anesthesia, hepatic artery embolization), administer intravenous octreotide at 50 mcg/hour starting 12 hours before, during, and 48 hours after the procedure to prevent carcinoid crisis 1, 5
Other Neuroendocrine Tumors
- For VIPomas: 200-300 mcg daily in 2-4 divided doses during initial 2 weeks; doses above 450 mcg/day are rarely required 2
- For glucagonomas: Octreotide has shown improvement in symptoms, though normalizing glucagon levels may be difficult due to massive circulating amounts 1
- For gastrinomas: High-dose proton pump inhibitors are adequate; some groups advise adding somatostatin analogues 1
Common Side Effects
- Gallbladder abnormalities and gallstones 2, 1
- Fat malabsorption and vitamin A and D malabsorption 1, 5
- Glucose metabolism alterations (hypoglycemia or hyperglycemia) 2
- Hypothyroidism - monitor thyroid levels periodically 2
- Gastrointestinal symptoms (diarrhea, nausea, abdominal discomfort) 2
- Bradycardia and cardiac conduction abnormalities 2