布地奈德
布地奈德 (Budesonide) 是一種**局部作用、高效能的糖皮質激素**（效力約為潑尼松龍的 15 倍），具有微弱的鹽皮質激素活性。 * **靶向釋放**：口服劑型通常採用腸溶包衣（如 Entocort EC®），延遲藥物溶解直至抵達十二指腸。這使得藥物能在腸道內發揮集中的局部抗發炎作用。 * **減少全身性副作用**：雖然會被吸收到門脈循環中，但布地奈德具有極高的**肝臟首過代謝率**。肝臟會在藥物進入全身血液循環前清除絕大部分，這大幅降低了典型全身性類固醇副作用（如多飲、多尿和多食）的風險。 * **臨床應用**：在獸醫學中主要用於標示外治療犬貓的**炎症性腸病 (IBD)**，特別是針對無法耐受或對傳統全身性類固醇無反應的病患。 * **成本與劑型**：藥物費用可能是一個限制因素；此外，由於人類用膠囊對小型獸醫病患來說通常劑量過大，此藥物經常需要透過特殊藥局重新調配成較小的劑量。
作用機制: Budesonide diffuses across cell membranes and binds with high affinity to cytosolic **glucocorticoid receptors (GR)**. * The receptor-ligand complex translocates to the nucleus → binds to glucocorticoid response elements (GREs) on DNA → alters gene transcription. * **Anti-inflammatory pathway**: Induces the production of **lipocortin-1 (annexin-1)** → inhibits **phospholipase A2** → blocks the release of arachidonic acid from membrane phospholipids → decreases the synthesis of potent inflammatory mediators (prostaglandins and leukotrienes). * Despite its high first-pass metabolism, it still causes significant suppression of the **hypothalamic-pituitary-adrenal (HPA) axis**.
各物種劑量
- Inflammatory Bowel Disease (IBD) (Clinical Pearl) · 1 - 3 mg/m2 or 1 - 3 mg/dog · PO · q24h · Chronic management; taper to lowest effective dose · Do not crush or chew capsules.
- Inflammatory Bowel Disease (IBD) (Clinical Pearl) · 1 mg/cat · PO · q24h · Chronic management; taper to lowest effective dose · May be compounded if standard sizes are too large, though this alters the enteric coating.
- Feline Asthma (Clinical Pearl) · 100 - 400 µg (1-2 puffs) · Inhalation · q12h · Chronic management · Administer via a feline-specific spacer mask (e.g., AeroKat).
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
給藥途徑
禁忌症
- Hypersensitivity to budesonide
- Patients with active GI ulcers
- Active systemic infections
- Diabetes mellitus
- Cataracts
不良反應
- Steroid hepatopathy
- HPA-axis suppression
- Hyperadrenocorticism (rare, but risk increases with hepatic dysfunction)
藥物相互作用
- CYP3A Inhibitors (e.g., ketoconazole, itraconazole, erythromycin) · May decrease the hepatic metabolism of budesonide, leading to increased systemic blood levels and a higher risk of glucocorticoid adverse effects.
- Antacids, H2-blockers, Proton Pump Inhibitors · May increase gastric pH, potentially causing premature dissolution of the enteric coating and reducing the drug's targeted efficacy in the intestines.
- Ketoconazole · Inhibits CYP3A4, significantly increasing systemic budesonide levels and risk of toxicity · major
- Itraconazole · Inhibits CYP3A4, increasing systemic budesonide levels · major
- Erythromycin · Inhibits CYP3A4, potentially increasing budesonide levels · moderate
- NSAIDs (e.g., Meloxicam, Carprofen) · Increased risk of gastrointestinal ulceration and bleeding · major
監測
- Resolution of clinical signs of IBD (vomiting, diarrhea, weight loss)
- Liver enzymes (ALP, ALT) for potential steroid hepatopathy
- Clinical signs of hyperadrenocorticism (PU/PD/PP, panting, alopecia)
過量
Acute oral overdoses are unlikely to be of much clinical concern, though massive overdoses may warrant gut evacuation. The lethal dose in mice is reported to be 200 mg/kg.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。