オクトレオチド酢酸塩
**オクトレオチド酢酸塩**は、天然ホルモンであるソマトスタチンの合成長時間作用型オクタペプチドアナログです。獣医療では主に、**インスリノーマ**（特に犬やフェレット）や**ガストリノーマ**などの神経内分泌腫瘍の補助療法として使用されます。 主な臨床的ポイント： - **インスリノーマの管理**: 腫瘍性β細胞からのインスリン放出を抑制することで血糖値の安定化を助けますが、受容体の発現の違いにより効果にはばらつきがあります。 - **乳び胸**: 内臓血流とリンパ液の産生を減少させることにより、乳び胸水の管理に適用外使用されることが増えています。 - **制限事項**: 1日複数回の皮下注射が必要であり、大型犬では非常に高額になる可能性があります。猫の先端巨大症には効果が証明されていません。
作用機序: **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.
動物種別の用量
- 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.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Known hypersensitivity to octreotide
有害事象
- Gastrointestinal upset
- Decreased dietary fat absorption
- Biliary sludging or gallstones (with prolonged use)
- Injection site pain
薬物相互作用
- 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
モニタリング
- Blood glucose (for insulinoma treatment)
- Clinical efficacy
過量投与
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.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。