デスモプレシン
**デスモプレシン (DDAVP)** は、天然の脳下垂体抗利尿ホルモンであるアルギニンバソプレシンの合成アナログです。構造が修飾されており、昇圧（血圧上昇）作用をほぼ排除しつつ、抗利尿作用を著しく増強しています。 獣医療では、主に以下の2つの臨床目的で使用されます： * **中枢性尿崩症 (CDI)：** 犬および猫のCDIの診断（反応試験による）および長期管理におけるゴールドスタンダードであり、重度の多尿および多飲を効果的に解消します。 * **フォン・ヴィレブランド病 (vWD)：** 特定のサブタイプのvWD患者において、周術期に凝固因子を一時的に増加させるために使用されますが、作用時間が短く、耐性（タキフィラキシー）が急速に発現するため、長期的な有用性は限られています。 **臨床のポイント：** 動物における経口バイオアベイラビリティは極めて低いため、獣医療ではヒト用の点鼻薬を**患者の結膜嚢（目）に局所投与**することが最も一般的であり、信頼性の高い非侵襲的な吸収経路を提供します。
作用機序: Desmopressin exerts its effects through two primary mechanisms based on its high affinity for specific receptors: * **Antidiuretic Action (Kidneys):** Desmopressin selectively binds to **V2 receptors** on the basolateral membrane of cells in the renal distal tubules and collecting ducts. This binding activates adenylate cyclase → increases intracellular cAMP → triggers the translocation and insertion of **aquaporin-2 (AQP2)** water channels into the apical membrane. This dramatically increases water permeability, allowing water to be reabsorbed passively back into the bloodstream, thereby concentrating the urine and reducing urine volume. * **Hemostatic Action (Endothelium):** Desmopressin binds to **V2 receptors** on vascular endothelial cells → stimulates the rapid exocytosis of Weibel-Palade bodies → releases stored **von Willebrand factor (vWF)** and **Factor VIII** into the plasma. It also increases plasminogen factor levels.
動物種別の用量
- Differentiate central diabetes insipidus from nephrogenic form · 1 drop into the conjunctival sac · topical · twice daily · 2-3 days · Dramatic reduction in water intake or >=50% increase in urine concentration gives strong evidence for ADH deficit.
- Central diabetes insipidus · 1-2 drops into the conjunctival sac · topical · once or twice a day · Duration of activity is 8-24 hours.
- Central diabetes insipidus · 1- 4 drops of the intranasal solution in the conjunctival sac · topical · once to twice daily
- Central diabetes insipidus · 2-5 micrograms · SC · once to twice daily · Using intranasal solution parenterally.
- Central diabetes insipidus (oral alternative) · 25-50 micrograms (total dose; 1/4th to 1/2 of a 100 microgram tablet) · PO · q12h · Dose and response may be variable.
- Diagnosis of diabetes insipidus · 20 micrograms · IV · Once
- Diagnosis of diabetes insipidus · 0.05 micrograms/kg · IV · Once · Dilute the nasal spray formulation (0.1 mg/ml) in sterile water. Measure USG every 2 hours. Increase to >=1.025 within 2-7 hours is consistent with central DI.
- Central diabetes insipidus · One drop placed in the conjunctival sac · topical · twice daily (or three times a day) · Using one drop three times a day usually returns urine production to normal.
投与経路
禁忌
- Hypersensitivity to desmopressin
- Type IIB or platelet-type (pseudo) Von Willebrand's disease (may cause platelet aggregation and thrombocytopenia; notably seen in German Shorthair Pointers)
- Hyponatraemia (specifically for modified water deprivation test)
- Renal disease (specifically for modified water deprivation test)
- Dehydration (specifically for modified water deprivation test)
- Hypercalcaemia (specifically for modified water deprivation test)
有害事象
- Eye irritation (following conjunctival administration)
- Hypersensitivity reactions
- Fluid retention (with overdosage)
- Hyponatremia (with overdosage)
- Headache (reported in humans)
薬物相互作用
- Chlorpropamide · May enhance the antidiuretic effects of desmopressin
- Fludrocortisone · May enhance the antidiuretic effects of desmopressin
- Urea · May enhance the antidiuretic effects of desmopressin
モニタリング
- Serum electrolytes (especially sodium)
- Urine osmolality and/or urine volume
- Bleeding times (when used for Von Willebrand's disease)
- Adrenocortical function (prior to water deprivation test)
- Serum sodium (Clinical Pearl)
- Urine specific gravity (Clinical Pearl)
- Bleeding times/vWF levels if used for bleeding disorders (Clinical Pearl)
過量投与
Chronic oral doses of 0.2 mg/kg/day have been given to dogs for 6 months without significant toxicity. However, acute or severe overdosage may lead to **fluid retention** and **hyponatremia** (water intoxication). > **Treatment:** Employ dosage reduction and strict fluid restriction. Monitor serum electrolytes (especially sodium) closely to prevent neurological complications associated with hyponatremia.
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。