octreotide acetate
Sandostatin, Sandostatin LAR Depot

Available forms
Available by prescription only
Injection: 0.05 mg/ml, 0.1 mg/ml, and 0.5 mg/ml in 1-ml ampules; 0.2 mg/ml and 1 mg/ml in 5-ml multidose vials
Injection suspension, extended-release: 10 mg/5 ml, 20 mg/5 ml, 30 mg/5 ml

Indications and dosages
 Flushing and diarrhea caused by carcinoid tumors. Adults: Initially, 100 to 600 mcg daily S.C. in two to four divided doses for first 2 weeks of therapy (usual daily dose, 300 mcg). Subsequent dosage based on individual response. Or, 50 to 500 mcg I.V., repeated p.r.n.; prolonged I.V. infusion (for example, 50 mcg/hour) infused over 8 to 24 hours also may be used. Or, 20 mg I.M. of suspension q 4 weeks for 2 months (after using injection for at least 2 weeks). Continue S.C. injection of immediate release for at least first 2 weeks of therapy with long-acting formulation. After 2 months, increase dose to 30 mg or decrease to 10 mg I.M. q 4 weeks, p.r.n.
 Prevention of carcinoid crisis from surgery. Adults: 250 to 500 mcg S.C. 1 to 2 hours before induction of anesthesia.
 Symptomatic treatment of watery diarrhea caused by vasoactive intestinal peptide-secreting tumors (VIPomas). Adults: Initially, 200 to 300 mcg daily S.C. in two to four divided doses for first 2 weeks of therapy. Subsequent dosage based on individual response, but usually won’t exceed 450 mcg daily. Also, 10 to 30 mg I.M. of suspension based on growth hormone concentration, insulin-like growth factor 1 (IGF-1), and symptom control q 4 weeks for 2 months (after using injection for at least 2 weeks). Continue S.C. injection of immediate release for at least first 2 weeks of therapy with long-acting formulation. After 2 months, increase dose to 30 mg or decrease to 10 mg I.M. q 4 weeks as needed.
 Acromegaly. Adults: Initially, 50 mcg t.i.d. S.C. Subsequent dosage based on individual response. Usual dosage is 100 to 200 mcg S.C. t.i.d. but some patients may need up to 500 mcg t.i.d. for maximum effectiveness. Patients currently receiving S.C. Sandostatin may be switched directly to Sandostatin LAR in a dose of 20 mg I.M. of suspension q 4 weeks for 3 months (after using S.C. injection for at least 2 weeks). After 3 months of receiving Sandostatin LAR, dosage adjustment is based on growth hormone level, IGF-1, and symptom control. Dose ranges from 10 to 40 mg I.M. q 4 weeks.

Pharmacodynamics
Antidiarrheal action: Octreotide mimics the action of naturally occurring somatostatin and decreases the secretion of gastroenterohepatic peptides that may contribute to adverse effects in patients with metastatic carcinoid tumors and VIPomas. It isn’t known if drug affects the tumor directly.

Pharmacokinetics
Absorption: Absorbed rapidly and completely after injection.
Distribution: Distributed to the plasma, where it binds to serum lipoprotein and albumin.
Metabolism: Eliminated from the plasma at a slower rate than the naturally occurring hormone. Apparent half-life is about 1 1/2 hours, with a duration of effect of up to 12 hours.
Excretion: About 35% appears unchanged in urine.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug or its components.

Interactions
Drug-drug. Cyclosporine: Decreases cyclosporine levels. Monitor patient closely.

Adverse reactions
CNS: dizziness, light-headedness, fatigue, headache.
CV: bradycardia, conduction abnormalities, arrhythmias.
EENT: blurred vision.
GI: nausea, diarrhea, abdominal pain or discomfort, loose stools, vomiting, fat malabsorption, gallstones or biliary sludge, flatulence, constipation.
GU: urinary frequency, urinary tract infection.
Metabolic: hyperglycemia, hypoglycemia, hypothyroidism, suppressed secretion of growth hormone and gastroenterohepatic peptides (gastrin, glucagon, insulin, motilin, pancreatic polypeptide, secretin, and VIP).
Musculoskeletal: backache, joint pain.
Skin: flushing, edema, wheals, erythema or pain at injection site, alopecia, pain or burning at S.C. injection site.
Other: flulike symptoms.

Effects on lab test results
• May increase or decrease glucose levels.

Overdose and treatment
Doses of 1,000 mcg have been administered as an I.V. bolus in volunteers without adverse effects. Drug may produce metabolic changes in certain patients.

Special considerations
• Fluid and electrolyte balance may be altered after start of octreotide therapy.
• Half-life may be altered in patients with end-stage renal failure who are undergoing dialysis. Dosage adjustment may be needed.
• Octreotide suspension must be given under clinical supervision. Suspension is for I.M. use only into the gluteal muscle and should be stored refrigerated at 36° to 46° F (2° to 8° C) and protected from light. Warm to room temperature for 30 to 60 minutes before mixing.
• I.V. injection may be given undiluted for carcinoid crisis. For I.V. infusion, dilute drug in 50 to 200 ml of normal saline solution or D₅W injection. Infuse over 15 to 30 minutes. Drug remains stable for 24 hours. Store ampules in the refrigerator. Drug may be stored at room temperature for 14 days. Injection is incompatible with total parenteral nutrition solution.
• Monitor baseline and periodic tests of thyroid function because long-term effects of drug on hypothalamic-pituitary function aren’t known.
• Monitor laboratory values during therapy, such as urinary 5-hydroxyindoleacetic acid, plasma serotonin, plasma substance P for carcinoid tumors, and plasma VIP for VIPomas.
• Drug may alter fat absorption and aggravate fat malabsorption. Periodically monitor 72-hour fecal fat and serum carotene.
• Drug may decrease vitamin B₁₂ levels during chronic treatment. Monitor patient’s vitamin B₁₂ levels.
• Patients with acromegaly are more likely to experience adverse GI effects and bradycardia.
Breast-feeding patients
• It isn’t known if drug appears in breast milk.
Pediatric patients
• Doses of 1 to 10 mcg/kg appear to be well tolerated in children.

Patient education
• Because drug may cause gallstones, tell patient to report abdominal discomfort promptly.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use