Steroid Dosing for Acute Interstitial Nephritis
For acute interstitial nephritis, oral prednisone at 1 mg/kg/day (maximum 60 mg/day) for 2-3 weeks followed by a gradual taper over 3 weeks is the recommended steroid regimen. 1, 2
Initial Treatment Approach
- Prompt discontinuation of the offending drug is the most important first step in management of drug-induced AIN 2
- Oral prednisone should be initiated at 1 mg/kg/day (maximum 60 mg/day) for 2-3 weeks 1, 2
- After the initial treatment period, steroids should be tapered gradually over approximately 3 weeks 1
Alternative Regimen: Pulse Steroid Therapy
- Intravenous methylprednisolone pulse therapy (30 mg/kg/day for 3 days, maximum 1g/day) followed by oral prednisone 1 mg/kg/day for 2 weeks with subsequent tapering is an alternative approach 1, 2
- Studies show no significant difference in outcomes between oral prednisone and pulse methylprednisolone regimens when used early in the disease course 2
Timing of Steroid Initiation
- Early initiation of steroid therapy is crucial for optimal recovery of kidney function 3
- Longer delays in starting steroid therapy correlate with poorer recovery (8 days for complete recovery vs. 35 days for no recovery) 3
- Patients should be started on steroids as soon as the diagnosis is confirmed by biopsy 1, 2
Duration of Treatment
- Total treatment duration typically ranges from 3-6 weeks depending on clinical response 1, 2
- Monitoring serum creatinine during treatment helps guide therapy duration 3
- A rapid decline in serum creatinine (>50% reduction) within the first week of treatment is associated with better outcomes 1
Expected Outcomes
- With appropriate steroid therapy, approximately 58-60% of patients achieve complete remission (eGFR ≥60 ml/min/1.73m²) 2
- Approximately 40-42% achieve partial remission (improvement in eGFR but remaining <60 ml/min/1.73m²) 2
- Factors associated with better outcomes include:
Common Pitfalls and Caveats
- Failure to promptly discontinue the offending drug significantly impairs recovery 2, 3
- Delaying steroid therapy beyond 7-10 days after diagnosis reduces the likelihood of complete recovery 3
- Proton pump inhibitors are increasingly recognized as important causes of AIN and often have longer exposure times before diagnosis, leading to poorer outcomes 3
- Patients with longer duration of drug exposure (>30 days) have significantly worse outcomes 3
Special Considerations
- In patients with immune checkpoint inhibitor-related AIN, higher doses of steroids may be required (methylprednisolone 500-1000 mg daily for 3 days) 4
- For patients with contraindications to systemic steroids, early consultation with nephrology is recommended to discuss alternative approaches 3
- Patients with severe AIN requiring dialysis at presentation may still benefit from steroid therapy, with studies showing reduced dialysis dependence at 6 months (3.2% vs 20.6%) in steroid-treated patients 5