Dosing considerations for oral acyclovir following neonatal herpes disease

Area of Science:

• Pediatric Infectious Diseases
• Virology
• Pharmacology

Background:

• Neonatal herpes simplex virus (HSV) infections can lead to significant morbidity and mortality.
• Recurrent HSV lesions occur in 8-30% of infants post-initial parenteral antiviral therapy.
• Long-term oral acyclovir is a potential strategy for preventing recurrent HSV disease in infants.

Purpose of the Study:

• To evaluate the efficacy and safety of oral acyclovir in preventing recurrent HSV disease in infants.
• To determine if specific oral acyclovir dosing achieves target plasma concentrations for effective disease prevention.
• To assess the impact of achieving target plasma acyclovir concentrations on recurrence rates and toxicity.

Main Methods:

• Nine infants with HSV disease (8 encephalitis, 1 recurrent dermal/ocular) received oral acyclovir.
• Dosing aimed for 2-hour post-plasma concentrations ≥ 2 µg/ml, targeting cerebrospinal fluid distribution.
• Patients were monitored for plasma acyclovir levels, clinical recurrence, and renal/neurologic toxicity.

Main Results:

• One of nine patients failed to achieve target plasma acyclovir concentrations.
• One of nine patients experienced symptomatic central nervous system recurrence.
• Eight of nine patients showed no recognized recurrence of dermal or neurologic HSV disease.
• No signs of acyclovir toxicity were observed during routine renal and neurologic monitoring.

Conclusions:

• Oral acyclovir dosing can achieve target plasma concentrations (≥ 2 µg/ml) in infants.
• Achieving target plasma acyclovir concentrations is associated with a low rate of recurrent HSV disease.
• Oral acyclovir appears safe for long-term use in infants with HSV disease, with no observed toxicity.