Under what circumstances should prescriptions of antiviral agents, such as acyclovir (Antiviral medication), be considered a priority and a herpes zoster (Shingles) booster recommended?

Antiviral Therapy and Herpes Zoster Booster Recommendations

Antiviral agents should be prioritized for immunocompromised patients, those with severe herpes infections, and individuals at high risk for viral reactivation, while herpes zoster vaccination should be recommended for prevention in susceptible populations. 1

Priority Circumstances for Antiviral Therapy

Immunocompromised Patients

• Patients with hematological malignancies, particularly those undergoing chemotherapy or stem cell transplantation, should receive antiviral prophylaxis during periods of immunosuppression 1
• High-risk cancer patients (allogeneic stem cell transplant recipients, patients on alemtuzumab therapy) require HSV and VZV prophylaxis with acyclovir, famciclovir, or valacyclovir for extended periods 1
• Patients receiving bortezomib therapy or purine analog therapy (e.g., fludarabine) should receive antiviral prophylaxis during active treatment 1

Active Herpes Infections

• Patients with acute herpes zoster (shingles) require prompt antiviral therapy, ideally within 72 hours of rash onset 1, 2
• Disseminated or invasive herpes zoster requires intravenous acyclovir and temporary reduction in immunosuppressive medication 1
• Primary varicella infection (chickenpox) in immunocompromised patients requires immediate antiviral therapy 2
• Genital herpes episodes (initial and recurrent) should be treated with appropriate antiviral therapy 2

Special Populations

• Kidney transplant recipients with HSV or VZV infections require antiviral treatment and possible adjustment of immunosuppressive medication 1
• HIV-infected patients with herpes infections may require higher doses of antiviral medications for longer duration 1
• Patients with inflammatory bowel disease on immunosuppressive therapy should receive antiviral treatment for HSV, VZV, or influenza infections 1

Herpes Zoster Vaccination Recommendations

• Varicella-susceptible patients after exposure to individuals with active varicella zoster infection should receive varicella zoster immunoglobulin within 96 hours of exposure 1
• If immunoglobulin is not available or more than 96 hours have passed, a 7-day course of oral acyclovir should be begun 7-10 days after varicella exposure 1
• HPV vaccination should be considered for eligible patients to prevent HPV-related cancers, particularly in immunosuppressed individuals 1

Treatment Algorithms

For Acute Herpes Zoster (Shingles):

1. Immunocompetent patients: Oral antiviral therapy (acyclovir, valacyclovir, or famciclovir) for 7 days 3, 4

   • Valacyclovir 1000mg three times daily for 7 days has shown better resolution of pain compared to acyclovir 3
   • Famciclovir regimens (once, twice, or three times daily) are comparable to acyclovir five times daily 5

2. Immunocompromised patients: More aggressive therapy required 6

   • For uncomplicated cases: Higher dose oral therapy (acyclovir, valacyclovir, famciclovir) 1
   • For complicated cases (multi-dermatomal, ophthalmic, visceral, disseminated): IV acyclovir 1, 6
   • Continue treatment for minimum 7-10 days and until all lesions have scabbed 1

For HSV Prophylaxis in High-Risk Patients:

1. Allogeneic stem cell transplant recipients: Acyclovir prophylaxis for at least 1 year after transplant 1
2. Alemtuzumab therapy: Minimum 2 months after treatment and until CD4 count ≥200 cells/mcL 1
3. Autologous stem cell transplant: During neutropenia and at least 30 days after transplant 1

Common Pitfalls and Caveats

• Delaying antiviral therapy beyond 72 hours of rash onset significantly reduces effectiveness for herpes zoster 4
• Immunosuppressed patients may require longer treatment courses and higher doses than immunocompetent individuals 1
• Acyclovir-resistant strains should be suspected if lesions persist despite appropriate therapy, particularly in immunocompromised patients 1
• Immunosuppressive therapy should be temporarily reduced or discontinued in severe cases of varicella infection, disseminated HSV/VZV, and other serious viral infections 1
• Patients on antiviral prophylaxis should still be monitored for breakthrough infections, especially during periods of increased immunosuppression 1