What is the recommended treatment for shingles in a patient with end-stage renal disease (ESRD) on peritoneal dialysis?

Treatment of Shingles in End-Stage Renal Disease on Peritoneal Dialysis

Antiviral agents should be used to treat shingles in ESRD patients on peritoneal dialysis, but dose adjustment is critical—valacyclovir should be reduced to 500 mg every 24 hours, and the medication must be given with extreme caution due to high risk of neurotoxicity, as peritoneal dialysis removes acyclovir poorly compared to hemodialysis. 1, 2

Antiviral Treatment Approach

First-Line Medication and Dosing

• Valacyclovir is the preferred oral antiviral agent, with FDA-approved dosing for herpes zoster in ESRD patients requiring adjustment based on creatinine clearance 2
• For patients with creatinine clearance <10 mL/min (which includes peritoneal dialysis patients), the recommended dose is 500 mg every 24 hours for herpes zoster, compared to the standard 1 gram every 8 hours in patients with normal renal function 2
• Treatment duration should be 7 days, initiated at the earliest sign of shingles 2

Critical Safety Considerations for Peritoneal Dialysis Patients

Peritoneal dialysis is significantly less effective than hemodialysis at removing acyclovir, which creates a particularly high risk situation 2, 3, 4:

• Acyclovir (the active metabolite of valacyclovir) has an elimination half-life of approximately 17 hours in ESRD patients on peritoneal dialysis, compared to 4 hours during hemodialysis 2, 4
• Peritoneal dialysis removes less than 10% of an administered acyclovir dose in 24 hours, with mean CAPD clearance of only 4.4 mL/min 4
• The pharmacokinetic parameters closely resemble those in ESRD patients not receiving any dialysis 2

Neurotoxicity Risk and Monitoring

Valacyclovir neurotoxicity is a common and serious complication in ESRD patients, even when doses are adjusted according to manufacturer recommendations 5, 3, 6:

• Manifestations include confusion, disorientation, visual hallucinations, altered mental status, and deterioration of consciousness 5, 3, 6
• Neurotoxicity can occur even with "appropriately adjusted" doses based on current guidelines, particularly in peritoneal dialysis patients where drug removal is minimal 3, 6
• Monitor closely for any neurological symptoms during the first 48-72 hours of treatment 5, 6

Management of Neurotoxicity if it Occurs

If neurotoxicity develops, immediate hemodialysis is the treatment of choice 3, 6:

• Hemodialysis effectively reduces plasma acyclovir concentrations and removes approximately one-third of acyclovir during a 4-hour session 2, 3
• Switching from peritoneal dialysis to hemodialysis has resulted in successful recovery in reported cases 3, 6
• Peritoneal dialysis alone is inadequate for treating acyclovir neurotoxicity due to negligible drug removal 3

Alternative Antiviral Options

Famciclovir

• Famciclovir is an alternative oral antiviral that also requires dose adjustment in renal impairment 7
• Standard dosing for herpes zoster is 500 mg every 8 hours for 7 days, but this must be reduced based on creatinine clearance 7
• Similar neurotoxicity concerns apply as with valacyclovir 7

Intravenous Acyclovir

• Intravenous acyclovir may be considered for severe or disseminated zoster 1
• Requires even more careful dose adjustment and monitoring in ESRD patients 3, 6

Infection Control Measures

Standard, contact, and airborne precautions are required for immunocompromised dialysis patients with herpes zoster 1:

• Airborne and contact precautions are needed when disseminated zoster is suspected (lesions in >3 dermatomes) or the patient is immunocompromised 1
• Physical separation of at least 6 feet from other patients is recommended 1
• Enhanced hand hygiene and environmental cleaning with virucidal agents 1

Key Clinical Pitfalls to Avoid

• Never use standard dosing of valacyclovir (1 gram every 8 hours) in peritoneal dialysis patients—this can lead to severe neurotoxicity and has resulted in deaths 5, 3
• Do not assume peritoneal dialysis will adequately clear acyclovir—it removes the drug poorly compared to hemodialysis 3, 4
• Do not dismiss neurological symptoms as unrelated—consider acyclovir neurotoxicity even if brain imaging and lumbar puncture are normal 3, 6
• Have a low threshold for switching to hemodialysis if any signs of neurotoxicity develop, as this is the only effective method for rapid drug removal 3, 6