What is the dose of acyclovir (antiviral medication) for viral meningitis in a 14-year-old male patient weighing 40 kilograms?

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Last updated: April 1, 2025View editorial policy

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From the Guidelines

For a 14-year-old boy weighing 40 kg with meningitis, the recommended dose of acyclovir is 10 mg/kg intravenously every 8 hours. Based on his weight, this would be approximately 400 mg per dose, administered three times daily 1. The medication should be infused over 1 hour to avoid renal toxicity. Adequate hydration should be maintained throughout treatment to protect kidney function. Acyclovir works by inhibiting viral DNA synthesis, making it effective against herpes simplex virus (HSV), which is a common cause of viral meningitis. Renal function should be monitored during treatment, and the dose may need adjustment if kidney function becomes impaired. Treatment should begin as soon as viral meningitis is suspected, as earlier treatment leads to better outcomes. Some key points to consider in the treatment of meningitis include:

  • The importance of distinguishing between HSV meningitis and HSV encephalitis, as the latter requires a longer course of treatment (14-21 days) 1
  • The need for suppressive therapy in patients with recurrent HSV-2 meningitis, although the optimal dose and duration of treatment are not well established 1
  • The potential for renal toxicity with acyclovir, and the need for adequate hydration and monitoring of renal function during treatment 1. It is essential to note that the treatment of viral meningitis should be individualized based on the specific cause of the infection and the patient's clinical presentation. In this case, the recommended dose of acyclovir is based on the most recent and highest quality evidence available 1.

From the FDA Drug Label

Herpes Simplex Encephalitis Sixty-two patients ages 6 months to 79 years with brain biopsy-proven herpes simplex encephalitis were randomized to receive either acyclovir (10 mg/kg every 8 hours) or vidarabine (15 mg/kg/day) for 10 days

  • The dose of acyclovir for a 14-year-old boy weighing 40 kg with meningitis is 10 mg/kg every 8 hours.
  • This dose is based on the treatment of herpes simplex encephalitis, which is a similar condition to meningitis.
  • The patient's weight is 40 kg, so the dose would be 400 mg every 8 hours 2.

From the Research

Acyclovir Dosage for Meningitis

The dosage of acyclovir for a 14-year-old boy weighing 40 kg with meningitis is not explicitly stated in the provided studies.

Relevant Studies

  • The study 3 compared empiric antibiotic and acyclovir usage before and after the introduction of an on-site FilmArray Meningitis/Encephalitis Panel in a pediatric hospital, but it does not provide information on the dosage of acyclovir.
  • The study 4 reviewed the clinical and cost implications of Biofire FilmArray® meningitis/encephalitis panel testing, but it also does not provide information on the dosage of acyclovir.
  • The study 5 reviewed empiric acyclovir prescribing practices for suspected viral central nervous system infections, but it does not provide information on the dosage of acyclovir.
  • The study 6 evaluated the role of viral polymerase chain reaction testing in patients with aseptic meningitis, but it does not provide information on the dosage of acyclovir.
  • The study 7 studied the impact of a 24/7 multiplex-PCR on the management of patients with confirmed viral meningitis, but it does not provide information on the dosage of acyclovir.

Key Points

  • None of the provided studies mention the specific dosage of acyclovir for a 14-year-old boy weighing 40 kg with meningitis.
  • The studies focus on the usage, duration, and reduction of acyclovir treatment in patients with suspected or confirmed meningitis, but do not provide dosage information.
  • To determine the appropriate dosage of acyclovir, it is recommended to consult a medical professional or refer to established clinical guidelines.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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