Prednisolone
**Prednisolone** is a potent, intermediate-acting synthetic corticosteroid widely used in veterinary medicine. In ophthalmology, it is considered the gold standard and most effective drug for the treatment of **anterior uveitis**. Key clinical distinctions exist between its formulations: * **Prednisolone Acetate**: Formulated as a suspension. It possesses superior anti-inflammatory activity and achieves *excellent penetration* into the anterior segment of the eye through the intact cornea, outperforming dexamethasone products. * **Prednisolone Sodium Phosphate**: Formulated as a solution. It does not penetrate the intact cornea as effectively as the acetate form but is useful for surface ocular inflammation. > **Clinical Pearl**: While applied topically to the eye, prednisolone can be absorbed systemically via the nasolacrimal duct and conjunctival vessels. In small animals (under 20 kg), frequent application can lead to systemic side effects, including the destabilization of diabetes mellitus.
Mecanismo: 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**.
Dosificación por especie
- 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.
Vías de administración
Contraindicaciones
- 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
Efectos adversos
- 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
Interacciones farmacológicas
- 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
Monitorización
- 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
Sobredosis
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.
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