What are the renal dosing guidelines for plaque nail treatment in patients with impaired renal function?

Renal Dosing for Plaque Nail (Onychomycosis) Treatment

I was unable to locate specific renal dosing guidelines for "plaque nail" as a distinct medication entity in the provided evidence. However, if you are referring to onychomycosis (fungal nail infection) treatment in patients with renal impairment, the following evidence-based recommendations apply:

Systemic Antifungal Agents Requiring Renal Dose Adjustment

Terbinafine

Terbinafine is contraindicated in patients with hepatic impairment and requires caution in renal impairment. 1

• Standard dosing: 250 mg per day for 12-16 weeks for toenail infections 1
• Renal impairment consideration: The British Association of Dermatologists guidelines list renal impairment as a contraindication/caution but do not provide specific dose adjustments 1
• Monitoring: Baseline liver function tests and complete blood count are recommended 1

Fluconazole

Fluconazole requires dose adjustment in renal impairment and may serve as an alternative when terbinafine or itraconazole cannot be tolerated. 1

• Standard dosing: 150-450 mg per week for at least 6 months for toenail infections 1
• Renal impairment: Listed as a contraindication/caution requiring adjustment 1
• Monitoring: Perform baseline liver function tests and full blood count; monitor liver function in high-dose or prolonged therapy 1

Itraconazole

Itraconazole is first-line treatment for dermatophyte onychomycosis but requires monitoring in patients with hepatotoxicity risk. 1

• Standard dosing: 200 mg per day for 12 weeks continuously, or pulse therapy at 400 mg per day for 1 week per month (3 pulses for toenails) 1
• Renal considerations: While not specifically contraindicated in renal disease, hepatic function monitoring is essential 1

Griseofulvin

Griseofulvin is contraindicated in liver impairment and has lower efficacy compared to terbinafine and itraconazole. 1

• Standard dosing: 500-1000 mg per day for 12-18 months for toenail infection 1
• Renal considerations: No specific renal dose adjustment mentioned, but avoid in hepatic impairment 1

Topical Therapy (No Renal Adjustment Required)

Topical antifungals do not require renal dose adjustment and are useful alternatives when systemic therapy is contraindicated. 1

• Amorolfine 5% lacquer: Applied once or twice weekly for 6-12 months 1
• Ciclopirox 8% lacquer: Applied once daily for up to 48 weeks 1
• Tioconazole 28% solution: Applied twice daily for 6-12 months 1

General Principles for Renal Dosing

For medications requiring renal adjustment, reduce dosing frequency rather than dose amount for concentration-dependent drugs to maintain efficacy. 1, 2

• Maintain the milligram dose at 12-15 mg/kg per dose while extending the interval to two or three times weekly 1, 2
• Serum drug concentrations should be monitored to avoid toxicity in patients with severe renal impairment 1, 2
• Smaller doses may reduce drug efficacy, so maintaining dose amount while extending intervals is preferred 2

Clinical Approach

In patients with chronic kidney disease requiring onychomycosis treatment:

1. Assess renal function using creatinine clearance or glomerular filtration rate 3
2. Consider topical therapy first if systemic contraindications exist 1
3. If systemic therapy needed: Choose fluconazole or itraconazole with appropriate monitoring, avoiding terbinafine if significant renal impairment present 1
4. Monitor closely for drug accumulation and adverse effects 3

Important Caveats

• Drug dosing errors are common in patients with renal impairment and can cause adverse effects 3
• Chronic kidney disease affects drug absorption, distribution, metabolism, and clearance 3
• Nephrotoxic drugs should be avoided entirely in patients with renal impairment 1
• Baseline and regular monitoring of renal parameters are necessary when using potentially nephrotoxic medications 2