プレドニゾロン
**プレドニゾロン**は、獣医療で広く使用されている強力な中時間作用型合成コルチコステロイドです。眼科領域では、**前ぶどう膜炎**の治療において最も効果的な薬剤であり、ゴールドスタンダードと見なされています。 製剤間で臨床的に重要な違いがあります： * **酢酸プレドニゾロン**：懸濁液として製剤化されています。優れた抗炎症作用を持ち、無傷の角膜を通過して眼の前眼部へ*非常に良好に浸透*し、デキサメタゾン製品よりも優れています。 * **リン酸ナトリウムプレドニゾロン**：水溶液として製剤化されています。無傷の角膜への浸透性は酢酸塩に劣りますが、眼表面の炎症に有用です。 > **臨床上のポイント**：眼への局所投与であっても、鼻涙管や結膜血管を介して全身に吸収される可能性があります。小型動物（20kg未満）では、頻繁な投与により糖尿病のコントロール悪化などの全身性副作用を引き起こす可能性があります。
作用機序: Prednisolone exerts its effects by diffusing across cell membranes and binding to specific cytosolic **glucocorticoid receptors**. The receptor-ligand complex translocates to the nucleus → binds to glucocorticoid response elements (GREs) on DNA → alters gene transcription. Mechanistically, it induces the synthesis of **lipocortin-1** (annexin-1), which inhibits the enzyme **phospholipase A2**. This inhibition prevents the release of **arachidonic acid** from membrane phospholipids, thereby potently shutting down the downstream synthesis of inflammatory mediators, including **prostaglandins** and **leukotrienes**.
動物種別の用量
- Severe anterior uveitis · 1 drop topically every hour; may be combined with subconjunctival corticosteroids · Topical / Subconjunctival · q1h · Re-evaluate 24 hours after beginning treatment · Ensure no underlying FHV-1 corneal ulceration is present.
- Moderate to mild uveitis / Post-operative anterior segment surgery · 1 drop topically · Topical · q6h (4 times daily) · Taper based on clinical response · Initial treatment, followed by tapering.
- Feline IMHA Induction · 3-4 mg/kg · PO · q24h · Until remission · May be combined with chlorambucil, ciclosporin, or mycophenolic acid.
- Severe anterior uveitis · Apply topically every hour; may be combined with subconjunctival corticosteroids · Topical / Subconjunctival · q1h · Re-evaluate 24 hours after beginning treatment · Equine Recurrent Uveitis (ERU) management.
- Moderate to mild uveitis / Post-operative anterior segment surgery · Apply topically · Topical · q6h (4 times daily) · Taper based on clinical response · Initial treatment, followed by tapering.
- Severe anterior uveitis · 1 drop topically every hour; may be combined with subconjunctival corticosteroids · Topical / Subconjunctival · q1h · Re-evaluate 24 hours after beginning treatment · Frequency depends on severity.
- Moderate to mild uveitis / Post-operative anterior segment surgery · 1 drop topically · Topical · q6h (4 times daily) · Taper based on clinical response · Initial treatment, followed by tapering.
投与経路
禁忌
- Corneal ulcers (absolute contraindication for topical use)
- Ocular viral infections (e.g., Feline Herpesvirus-1)
- Ocular fungal infections
- Use with extreme caution in patients with uncontrolled diabetes mellitus or systemic infectious diseases
- Pregnant animals
- Renal disease (systemic use)
- Diabetes mellitus (systemic use)
- Ulcerative keratitis (topical ophthalmic use)
- Systemic fungal infections
- Concurrent NSAID administration
- Corneal ulcers
有害事象
- Systemic absorption leading to iatrogenic hyperadrenocorticism (PU/PD/PP, panting, alopecia)
- Insulin resistance and destabilization of diabetes mellitus
- Delayed corneal healing
- Potentiation or exacerbation of ocular infections (bacterial, viral, fungal)
- Corneal degeneration or calcification (with long-term topical use)
- Hypothalamic-pituitary axis (HPA) suppression
- Adrenal atrophy
- Proteinuria and glomerular changes (dogs)
- Weight loss and muscle atrophy (catabolic effects)
- Iatrogenic hyperadrenocorticism (Cushing's syndrome)
- Vomiting and diarrhoea
- Gastrointestinal ulceration
- Hyperglycaemia
- Decreased serum T4 values
- Impaired wound healing
薬物相互作用
- Topical NSAIDs (e.g., flurbiprofen, diclofenac) · Concurrent use may increase the risk of delayed corneal healing or corneal melting, though sometimes used together cautiously for severe inflammation.
- Insulin · Systemically absorbed prednisolone antagonizes insulin, increasing blood glucose and complicating diabetes regulation. · major
- Systemic NSAIDs · Increased risk of gastrointestinal ulceration if significant systemic absorption of prednisolone occurs.
- NSAIDs · Increased risk of gastrointestinal ulceration · major
- Acetazolamide · Increased risk of hypokalaemia · moderate
- Amphotericin B · Increased risk of hypokalaemia · moderate
- Potassium-depleting diuretics (e.g., furosemide, thiazides) · Increased risk of hypokalaemia · moderate
- Phenytoin · Enhanced metabolism of corticosteroids · moderate
- Phenobarbital · Enhanced metabolism of corticosteroids · moderate
- Itraconazole · Decreased metabolism of corticosteroids · moderate
- Ciclosporin · Synergistic immunosuppression; may alter pharmacokinetics · moderate
モニタリング
- Resolution of clinical signs of uveitis (aqueous flare, miosis, pain, photophobia)
- Intraocular pressure (IOP) to monitor for secondary glaucoma
- Fluorescein staining (to ensure no corneal ulceration develops)
- Blood glucose and water intake/urine output in diabetic or small patients
- Clinical response to therapy
- Haematocrit (in cases of IMHA)
- Blood glucose (risk of hyperglycaemia)
- Serum T4 values (may be decreased)
- Renal parameters and urinalysis (proteinuria in dogs)
- Signs of GI ulceration (vomiting, melaena)
- Haematology at each visit (including 4 and 8 weeks after cessation of therapy)
- PCV (Packed Cell Volume)
- Liver parameters (especially if combined with azathioprine)
- Clinical signs of anaemia or GI bleeding
過量投与
Acute overdose from topical ophthalmic application is highly unlikely to cause severe toxicity. However, **chronic overdosage** or overly frequent application (especially in small patients <20 kg) can lead to systemic absorption resulting in **iatrogenic hyperadrenocorticism** (Cushing's syndrome), adrenal suppression, and destabilization of blood glucose in diabetic patients. If a corneal ulcer is present, overuse can lead to rapid corneal melting and perforation.
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。