Valacyclovir neurotoxicity can be effectively managed by hemodialysis

Valacyclovir-associated neurotoxicity among patients on hemodialysis and peritoneal dialysis: A nationwide population-based study

Whether valacyclovir-associated neurotoxicity (VAN) occurs more frequently in patients with end-stage renal disease (ESRD) on dialysis is unknown. This is the first population-based study to examine the risk of VAN associated with ESRD patients on dialysis. Among 2,284,800 patients diagnosed as having herpes zoster from 2002 to 2016, patients with ESRD on dialysis and individuals with normal renal function were enrolled in this study. Following propensity score matching, we compared the risk of altered mental status between valacyclovir users and non-users in the ESRD and normal renal function cohorts over a 30-day follow-up period. In the ESRD cohort, the incidence of altered mental status was 1.68 and 0.52 per 1,000 person-day in valacyclovir users and non-users, respectively, with an adjusted hazard ratio (HR) of 3.22 (95% confidence interval [CI]: 2.04–4.99, P < 0.001). The incidence of altered mental status of valacyclovir users on hemodialysis (HD) and peritoneal dialysis (PD) was higher than that of non-users. The adjusted HR was 3.20 (95% CI: 1.98–5.15, P < 0.001) for those on HD and 3.44 (95% CI: 1.13–10.49, P = 0.030) for those with PD. However, altered mental status was not observed in patients on HD receiving ≤500 mg of valacyclovir three times per week or in those on PD receiving ≤500 mg of valacyclovir per day. The findings demonstrate that adjusting the valacyclovir dosage and monitoring VAN in patients with HD and PD who have herpes zoster is crucial.

Neurotoxicity associated with acyclovir and valacyclovir: A systematic review of cases

WHAT IS KNOWN AND OBJECTIVE

Acyclovir and valacyclovir are commonly used antivirals with good general tolerance. Despite their good safety profile, they can cause systemic adverse effects, such as neurotoxicity, which are less frequent and known. The objective of this review was to collect all the reported cases of neurotoxicity associated with acyclovir and valaciclovir published in the literature and characterize their clinical course and interventions.

METHODS

A systematic review of cases was carried out following the guidelines established by "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA). The research was carried out using the PubMed-Medline and Embase databases, between July 1984 and March 2021.

RESULTS AND DISCUSSION

A total of 119 cases with neurotoxicity mainly related to acyclovir (n = 88; 73.9%), followed by valaciclovir (n = 35; 29.4%) were analysed. 49.6% (n = 59) were men with a mean age of 59.5 years ± 21.1 (0.5-88). In 83.3% of the cases, renal impairment was documented and 57.1% (n = 68) with end-stage renal disease. The administered dose was higher than the renal adjustment recommendations in 59.7% of the cases. The global mean of onset of symptoms was 3.1 days ± 4.3 (0.2-28) after the start of antivirals. The mean recovery time was 9.8 days ± 21.7 (0.2-180). 74.4% of the patients had a recovery of ≤7 days, 15.9% between 8 and 15 days and 9.8% > 15 days.

WHAT IS NEW AND CONCLUSION

The neurotoxicity induced by acyclovir and its derivative valacyclovir is a poorly known and rare adverse effect that can occur mainly in patients with advanced age and impaired renal function. The most characteristic symptoms are confusion, altered level of consciousness, hallucinations, agitation and dysarthria. The basis of treatment is the discontinuation of the antiviral, and in some cases, it may require additional clearance by dialysis.

Response to "Comment On: Acute Retinal Necrosis: Is the Current Valacyclovir Regimen Adequate?"

Acute Retinal Necrosis (ARN) is a potentially devastating form of Uveitis. Antivirals are the mainstay treatment for this syndrome. In this letter, we question the current oral Valacyclovir dosage, based on the experience we had with a recent unresponsive ARN case.

A Unique Case of Valacyclovir Toxicity and Pseudobulbar Affect in a Patient On Peritoneal Dialysis

There are a few cases of valacyclovir-associated neurotoxicity (VAN) reported. This case report documents a case of a 55-year-old male presenting with emotional lability or pseudobulbar affect as the predominant or sole manifestation of VAN. A failure to adjust valacyclovir's dose for herpes simplex infection in the setting of dialysis-dependent end-stage renal disease (ESRD) preceded VAN in this patient. The patient presented with involuntary and uncontrollable outbursts of emotion. Computerized tomography (CT) scan identified no underlying cause. A complete neurological examination with cognitive assessment was performed, with no abnormalities. He benefited from the use of aggressive peritoneal dialysis (PD) that was employed to enhance valacyclovir's clearance in this case of intractable VAN. On discharge, the patient was back to baseline mental function. Traumatic brain injury, neoplasm, vascular lesions, metabolic abnormality, neurological disease, herpetic encephalitis, and disorders of mood were ruled out. This led to the hypothesis of encephalopathy due to valacyclovir intoxication. Given that the clinical manifestations were related to ESRD, a dose-adjustment of valacyclovir is imperative in the setting of ESRD to prevent VAN. Our case presents important clinical variations. Firstly, our patient demonstrates that VAN may present with no focal neurological impairment, but pseudobulbar affect. Secondly, aggressive PD was useful in this case for the treatment of VAN as opposed to hemodialysis. We believe that it cleared valacyclovir resulting in the resolution of symptoms.

Severe mental disorders following anti-retroviral treatment in a patient on peritoneal dialysis: A case report and literature review

BACKGROUND

Antiviral drugs are widely used in populations with viral infection caused by immunologic inadequacy. Because these drugs are mainly metabolized by the kidneys, patients with renal failure undergoing renal replacement therapy are prone to drug adverse effects and poisoning. Severe neurotoxicity caused by antiviral drugs is a rare but life-threatening complication.

CASE SUMMARY

This study reported one male patient on peritoneal dialysis who suffered from severe mental disorders after receiving an overdose of acyclovir and valacyclovir for the treatment of herpes zoster. The literature review suggested that hemodialysis is better than peritoneal dialysis to clear acyclovir from the circulation. The patient died after his consciousness deteriorated despite peritoneal dialysis and continuous blood purification.

CONCLUSION

This case emphasizes cautiousness when using anti-retroviral drugs in patients with uremia. Hemodialysis is optimal method to remove the drugs.

Acyclovir Neurotoxicity in a Peritoneal Dialysis Patient: Report of a Case and Review of the Pharmacokinetics of Acyclovir

BACKGROUND The elderly population in the United States and the world is rapidly increasing. With aging, immunity and kidney function decrease, thus predisposing people to viral illnesses for which there is no effective prophylaxis. Herpes zoster afflicts the elderly and other immunocompromised patients, like those with end-stage renal disease, transplant recipients, and cancer patients, causing significant morbidity and sometimes mortality. Treating herpes zoster becomes problematic when the regular pharmacokinetics of the antiviral drugs are disturbed. CASE REPORT An 83-year-old African American man with end-stage kidney disease (ESRD) and on chronic peritoneal dialysis (PD) developed herpes zoster, for which he received the manufacturer-recommended intravenous dose of acyclovir. Shortly after taking the medication, he developed confusion, disorientation, and visual hallucinations. He was switched from PD to hemodialysis (HD), with successful recovery. Examination of the cerebrospinal fluid for meningitis and imaging studies of the head were negative. Serum levels of acyclovir were elevated. CONCLUSIONS Even when the acyclovir dose is properly adjusted for kidney function based on the current manufacturer's recommendations, it can cause neurotoxicity. Here, we discuss the pharmacokinetics of acyclovir and make some recommendations with regard to dose adjustment in patients with ESRD.

When a Seemingly Harmless Prescription Turns into Toxicity

Valacyclovir neurotoxicity is commonly seen in the elderly and those with impaired renal function. Differential diagnosis can be challenging as a myriad of medical conditions, including herpes zoster virus associated encephalitis, may present in a similar fashion. We present a case of a 71-year-old male who presented with altered mental status in the setting of recent herpes zoster eruption. His condition was attributed to valacyclovir neurotoxicity, and initiation of appropriate supportive therapy was met with complete resolution of symptoms and normalization of cognitive function.

Valacyclovir Neurotoxicity and Nephrotoxicity in an Elderly Patient Complicated by Hyponatremia

A 66-year-old women with no history of renal disease was admitted due to a coma and acute kidney injury with a serum creatinine level of 7.44 mg/dL which were ascribed to valacyclovir neurotoxicity and nephrotoxicity, respectively. She had received valacyclovir at a standard dosage for the treatment of herpes zoster and was finally discharged, having fully returned to her normal baseline mental status with a recovered serum creatinine level of 0.68 mg/dL. We feel that awareness of this pathology remains a challenge for physicians and therefore strongly recommend the further accumulation of experiences similar to our own. Our experience underscores the pitfalls of administering valacyclovir to elderly patients who barely appear to have a favorable renal function. Several concerns regarding the therapeutic management, including blood purification strategies, that emerged in this case are also discussed.

[Periodic synchronous discharge occurred in an elderly with acute valacyclovir-associated encephalopathy]

An 81-year-old woman suffering from sarcoidosis, chronic renal failure caused by hypertention was treated by valacyclovir 500 mg/day, for the diagnosis of herpes zoster of her right back. Her consciousness gradually became worse, and 3 days after taking the drug, she was sent to the emergency department of the hospital. Her conscious level was E2V2M5 (Glasgow Coma Scale) and myoclonus especially in her lower extremities occurred. Head CT and MRI show no obvious, acute abnormal findings other than chronic ischemic lesions, while an electroencephalogram (EEG) shows periodic synchronous discharges (PSDs) and disorganized background activity. Based on these findings, she was diagnosed as valacyclovir-associated acute encephalopathy. After conservative therapy of maintenance hemodialysis, her consciousness gradually improved, and PSDs disappeared accordingly and background activity of EEG became improved. In this case report, we presented valacyclovir-associated neurotoxicity with PSDs in EEG as potentially a surrogate marker. We should be cautious to use valaciclovir which may cause drug-induced encephalopathy especially in elderly or patients with renal failure even though the dose was adjusted in advance.

Intensification of peritoneal dialysis improves valacyclovir neurotoxicity

Valacyclovir induced neurotoxicity is a life-threatening complication, usually starting 24-48 h after drug-peak serum concentrations. The elderly with impaired renal function seem to be the most susceptible group to valacyclovir neurotoxicity. Although hemodialysis is considered the best method for rapid drug removal, our case showed that intensive peritoneal dialysis regimen leads to the recovery of neurotoxicity after 3 days.