From the Guidelines
Acyclovir is indicated for the treatment of herpes zoster (shingles) to reduce the severity and duration of the infection, particularly in immunocompromised patients or those with severe cases. The recommended dosage for immunocompetent adults is 800 mg orally five times daily for 7-10 days, ideally started within 72 hours of rash onset for maximum effectiveness 1. For patients with renal impairment, dose adjustment is necessary based on creatinine clearance.
Key Considerations
- Intravenous acyclovir (10 mg/kg every 8 hours for 7-10 days) may be used for severe cases or in immunocompromised patients, as high-dose IV acyclovir remains the treatment of choice for VZV infections in compromised hosts 1.
- Acyclovir works by inhibiting viral DNA polymerase, preventing herpes virus replication.
- Early treatment is crucial as it can reduce acute pain, accelerate rash healing, and may decrease the risk of postherpetic neuralgia, particularly in older adults.
- Common side effects include nausea, headache, and dizziness, while adequate hydration should be maintained during treatment to prevent crystalluria.
Patient-Specific Factors
- For immunocompromised patients, such as those undergoing chemotherapy or recipients of allogeneic blood and bone marrow transplants, antiviral therapy should be initiated promptly to prevent dissemination and chronic ulcerations 1.
- Patients with a history of VZV exposure are at risk for future reactivation infection, and acyclovir prophylaxis (800 mg bid) or valacyclovir (500 mg bid) may be considered during the first year following transplant to prevent VZV reactivation 1.
From the FDA Drug Label
Herpes Zoster Infections : Acyclovir tablets is indicated for the acute treatment of herpes zoster (shingles). The indication of acyclovir in herpes zoster is for the acute treatment of the condition, also known as shingles.
- The treatment is most effective if started within the first 48 hours of rash onset.
- Key benefits of acyclovir treatment in herpes zoster include shortening the times to lesion scabbing, healing, and complete cessation of pain, and reducing the duration of viral shedding and the duration of new lesion formation 2.
From the Research
Indication of Acyclovir in Herpes Zoster
- Acyclovir is a specific and selective inhibitor of the replication of Herpesviridae family, with well-documented efficacy and tolerability in the treatment of herpes zoster 3.
- Acyclovir has been shown to reduce various herpes zoster-related symptoms, as well as the duration, intensity, and prevalence of zoster-associated pain (ZAP) 4.
- However, acyclovir does not influence postherpetic neuralgia, a common complication of herpes zoster 4, 5.
- The use of acyclovir in the treatment of herpes zoster is beneficial when initiated within 72 hours of symptom onset, particularly in elderly immunocompetent patients and immunocompromised patients with uncomplicated herpes zoster 4.
Comparison with Other Antiviral Agents
- Valaciclovir, a derivative of acyclovir, has been shown to be more effective in accelerating the resolution of herpes zoster-associated pain and offers a simpler dosing regimen compared to acyclovir 3, 6.
- Famciclovir, another antiviral agent, has also been shown to be effective in reducing the duration of postherpetic neuralgia and is comparable to acyclovir in terms of efficacy 5, 6.
- A systematic review of high-quality randomized controlled trials has found that valaciclovir and famciclovir are superior to acyclovir in reducing the risk of herpes-zoster-associated pain 6.
Clinical Use
- Acyclovir is typically administered at a dose of 800 mg five times daily for 7 days in the treatment of herpes zoster 3, 4.
- The use of acyclovir in pregnant women with genital herpes and its role in decreasing the sexual transmission of genital herpes require further research 7.
- The efficacy and cost-effectiveness of acyclovir in treating herpes zoster in people below the age of 50 years also require further study 7.