From the FDA Drug Label
Herpes Zoster Infections:Acyclovir tablets are indicated for the acute treatment of herpes zoster (shingles). In a double-blind, placebo-controlled study of immunocompetent patients with localized cutaneous zoster infection, acyclovir (800 mg 5 times daily for 10 days) shortened the times to lesion scabbing, healing, and complete cessation of pain, and reduced the duration of viral shedding and the duration of new lesion formation The most frequent adverse event reported during 3 clinical trials of treatment of herpes zoster (shingles) with 800 mg of oral acyclovir 5 times daily for 7 to 10 days in 323 patients was malaise (11. 5%).
The causes of Herpes Zoster (shingles) are not directly stated in the provided drug labels. The risk factors for Herpes Zoster are not directly stated in the provided drug labels. The preventive measures for Herpes Zoster are not directly stated in the provided drug labels. The signs and symptoms of Herpes Zoster include:
- Lesion scabbing
- Lesion healing
- Pain
- Viral shedding
- New lesion formation
- Malaise The treatment for Herpes Zoster includes acyclovir tablets, which can be administered at a dose of 800 mg 5 times daily for 7 to 10 days 1, 1.
From the Research
Introduction to Herpes Zoster (Shingles)
Herpes Zoster, commonly known as shingles, is a condition that results from the reactivation of the latent varicella-zoster virus (VZV), which initially causes chickenpox in childhood 2, 3, 4. This reactivation leads to a painful, vesicular rash that is typically distributed unilaterally along a dermatomal pattern.
Causes and Risk Factors
The primary cause of Herpes Zoster is the reactivation of VZV. Risk factors for developing shingles include older age, conditions that decrease cell-mediated immunity, and a history of chickenpox 3, 4. Individuals with immunocompromising diseases or treatments are at a higher risk of developing shingles and its complications.
Preventive Measures
Prevention of Herpes Zoster is primarily through vaccination. The varicella-zoster virus vaccine, such as Zostavax and the newer recombinant subunit vaccine Shingrix, has been shown to significantly reduce the risk of developing shingles in older adults 2, 3, 4. Shingrix, in particular, has demonstrated a high vaccine efficacy rate and is recommended for individuals 50 years of age and older.
Signs and Symptoms
The signs and symptoms of Herpes Zoster include a painful rash that progresses through stages of vesicle formation, pustulation, ulceration, and crusting 2, 3. Prodromal symptoms such as malaise, headache, and low-grade fever may occur before the rash appears. The rash is usually confined to a single dermatome and is typically unilateral.
Treatment
Treatment for Herpes Zoster involves the use of antiviral agents such as acyclovir, valacyclovir, or famciclovir, ideally within 72 hours of the development of the rash 3. Pain management is also crucial and may include the use of topical lidocaine or capsaicin and oral gabapentin, pregabalin, or tricyclic antidepressants. For postherpetic neuralgia, a common complication of shingles, treatment focuses on symptom control and may involve the use of calcium channel α2-δ ligands, tricyclic antidepressants, or topical lidocaine patches 5.
Complications and Differentials
Postherpetic neuralgia is a significant complication of Herpes Zoster, characterized by pain that persists for months to years after the resolution of the rash 3, 5. Other complications may include vision loss and, rarely, stroke. Differentials for Herpes Zoster include other causes of vesicular rashes, such as herpes simplex virus infection.
Treatment Dosages and Durations
- Antiviral agents: The dosage and duration of antiviral treatment may vary depending on the specific medication and the individual's condition. For example, acyclovir may be given at a dose of 800 mg five times a day for 7-10 days.
- Pain management: The dosage and duration of pain management medications will depend on the severity of the pain and the individual's response to treatment. For example, gabapentin may be started at a dose of 300 mg three times a day and titrated up as needed.
Caveats
It is essential to note that while vaccination can significantly reduce the risk of developing shingles, it is not 100% effective. Individuals who have already had shingles can still benefit from vaccination to prevent future episodes 6. Additionally, the safety and efficacy of vaccines in severely immunocompromised individuals are being studied, and recommendations may vary depending on the individual's condition.