Octreotide Acetate
**Octreotide acetate** is a synthetic, long-acting octapeptide analog of the naturally occurring hormone somatostatin. In veterinary medicine, it is primarily utilized as an adjunctive therapy for neuroendocrine tumors such as **insulinomas** (especially in dogs and ferrets) and **gastrinomas**. Key clinical points: - **Insulinoma Management**: Helps stabilize blood glucose by inhibiting insulin release from neoplastic beta cells, though efficacy is variable due to receptor expression differences. - **Chylothorax**: Increasingly used off-label to manage chylous effusions by decreasing splanchnic blood flow and lymphatic fluid production. - **Limitations**: Requires multiple daily subcutaneous injections and can be cost-prohibitive for large breed dogs. It has not proven effective for feline acromegaly.
Mecanismo: **Octreotide** mimics natural somatostatin by binding to **somatostatin receptors (SSTRs)** on target cells. Mechanism pathway: **Octreotide** → binds to **SSTRs** (G-protein coupled receptors) → inhibits **adenylyl cyclase** → decreases intracellular **cAMP** → reduces calcium influx → inhibits exocytosis of secretory vesicles. This leads to the potent suppression of multiple endocrine and exocrine secretions, including: - **Insulin** and **glucagon** from the pancreas. - **Gastrin**, **secretin**, and **motilin** from the gastrointestinal tract. - **Growth hormone (GH)** from the anterior pituitary. *Note*: Humans possess 5 SSTR subtypes, whereas dogs primarily express one, which may explain the variable clinical response seen in canine insulinoma patients.
Dosificación por especie
- Adjunctive treatment of chylothorax · 10-20 micrograms/kg · SC · three times a day · 2-3 weeks · Prolonged treatment should be discouraged because people treated for longer than 4 weeks are at risk for gallstones.
- Medical treatment of insulinoma (particularly in patients refractory to or unable to tolerate other medical or surgical therapy) · 1-2 micrograms/kg · SC · 2-3 times a day
- Medical treatment of insulinoma (beta cell tumor) particularly in patients refractory to or unable to tolerate other medical or surgical therapy · 10-40 micrograms (total dose per dog) · SC · 2-3 times a day · Used in combination with dietary, glucocorticoid, and diazoxide treatment.
- Medical treatment of insulinoma · 2-4 micrograms/kg · SC · q8-12h · Further studies needed to determine octreotide's efficacy and safety.
- Adjunctive treatment of gastrinoma · 2-20 micrograms/kg · SC · three times daily · With omeprazole.
- Adjunctive treatment of chylothorax · 10-20 micrograms/kg · SC · three times a day · 2-3 weeks · Prolonged treatment should be discouraged because people treated for longer than 4 weeks are at risk for gallstones.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Known hypersensitivity to octreotide
Efectos adversos
- Gastrointestinal upset
- Decreased dietary fat absorption
- Biliary sludging or gallstones (with prolonged use)
- Injection site pain
Interacciones farmacológicas
- Beta-blockers · May cause additive bradycardic effects
- Bromocriptine · May increase oral bioavailability
- Calcium-channel blockers · May cause additive bradycardic effects
- Cyclosporine · May reduce cyclosporine levels
- Diuretics · May enhance fluid/electrolyte imbalances
- Food · May reduce fat absorption
- Insulin, oral hypoglycemics · Octreotide can inhibit insulin
- Quinidine · May reduce the quinidine clearance
Monitorización
- Blood glucose (for insulinoma treatment)
- Clinical efficacy
Sobredosis
Serious adverse effects are unlikely with acute overdose. In humans, subjects have received up to 120 mg IV over 8 hours with no untoward effects. Monitor for profound hypoglycemia or gastrointestinal distress and provide supportive care if needed.
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.