Somatostatin is a synthetic cyclic tetradecapeptide identical to the naturally occurring hypothalamic hormone somatostatin-14. It is a potent inhibitor of endocrine and exocrine secretion. The 12mg formulation is a long-acting release (LAR) depot injection, administered intramuscularly, designed for monthly administration to provide sustained therapeutic levels. It is primarily used for the long-term management of acromegaly and severe gastroenteropancreatic (GEP) neuroendocrine tumors (NETs).
Adult: Acromegaly & NETs: Initial dose is 20mg IM every 4 weeks. After 3 months, dose may be titrated based on GH/IGF-1 levels (acromegaly) or symptom control (NETs). Maintenance dose range: 10mg, 20mg, or 30mg every 4 weeks. The 12mg strength is often used as part of a tailored regimen or for specific dose adjustments. It is NOT the typical starting monotherapy vial.
Note: For 12mg LAR vial: 1. Aseptically reconstitute the powder with 2-5 mL of the provided Sterile Water for Injection. 2. Shake vial vigorously immediately after adding diluent and just before administration until a uniform milky suspension forms. 3. Draw up suspension into a syringe with a 19-21G needle. 4. Administer immediately via DEEP INTRAMUSCULAR injection into the upper outer quadrant of the gluteus. Do not inject intravenously or subcutaneously. Rotate injection sites. Administer at room temperature.
Somatostatin binds with high affinity to somatostatin receptors (SSTRs), particularly subtypes 2 and 5. This binding inhibits adenylate cyclase, reduces intracellular cAMP, and modulates calcium and potassium channels. The net effect is a potent, broad-spectrum inhibition of secretion from endocrine and exocrine glands. In acromegaly, it suppresses pathological GH secretion from pituitary adenomas and subsequent IGF-1 production. In NETs, it controls symptoms of carcinoid syndrome and VIPomas by inhibiting the secretion of serotonin, VIP, and other peptides, and may have direct antiproliferative effects on tumor cells.
Pregnancy: Category B: Animal studies show no risk, but no adequate, well-controlled studies in pregnant women. Use only if clearly needed.
Driving: May cause dizziness, fatigue, or hypoglycemia. Patients should be cautioned about operating machinery or driving until they know how the drug affects them.
| Cyclosporine | Somatostatin may decrease cyclosporine blood levels. Monitor levels closely. | Major |
| Oral Hypoglycemic Agents / Insulin | Somatostatin alters glucose homeostasis; may potentiate or antagonize their effects. Frequent glucose monitoring required. | Major |
| Bromocriptine | Somatostatin may increase the bioavailability of bromocriptine. | Moderate |
| Beta-blockers (e.g., Propranolol) | Additive effect on heart rate reduction; may cause severe bradycardia. | Moderate |
| Calcium Channel Blockers (e.g., Verapamil, Diltiazem) | Additive effect on heart rate reduction. | Moderate |
Same composition (Somatostatin (12mg)), different brands: