From the Guidelines
Internal shingles typically responds to acyclovir within 24-72 hours when treatment is started promptly. The standard regimen for acyclovir is 800 mg five times daily for 7-10 days. For optimal results, treatment should begin within 72 hours of rash onset, as earlier initiation leads to faster resolution of symptoms and reduced risk of complications, as supported by the study published in 2007 1. Patients may notice reduced pain, decreased formation of new lesions, and faster healing of existing lesions.
Treatment Considerations
- Alternative antiviral medications include valacyclovir (1000 mg three times daily for 7 days) and famciclovir (500 mg three times daily for 7 days), which may offer better compliance due to less frequent dosing.
- These medications work by inhibiting viral DNA synthesis, preventing the herpes zoster virus from replicating.
- Adequate hydration and pain management should accompany antiviral therapy.
- A more recent study published in 2021 1 emphasizes the importance of antiviral treatment in immunosuppressed patients, recommending oral valacyclovir or famcyclovir for uncomplicated herpes zoster and intravenous acyclovir for complicated cases.
Special Considerations
- If symptoms worsen despite treatment or if the patient is immunocompromised, they should seek immediate medical attention as more aggressive therapy may be needed.
- The 2021 study 1 also suggests that immunosuppressive therapy should be discontinued in severe cases of varicella infection and withheld in cases of measles, highlighting the need for careful management in immunocompromised patients.
From the FDA Drug Label
Herpes Zoster Infections: 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 question asks about internal shingles, but the provided text only discusses cutaneous zoster infection. Internal shingles is not directly addressed in the provided drug labels. The FDA drug label does not answer the question.
From the Research
Response to Acyclovir
- The response time of internal shingles to acyclovir is not directly stated in the provided studies, but the efficacy of acyclovir in treating herpes zoster is discussed 2, 3, 4, 5, 6.
- Acyclovir is taken 5 times daily for 7 days, and it appears to shorten the duration of post-herpetic neuralgia (PHN) to a similar degree as other antiviral drugs like famciclovir and valaciclovir 2.
- A study comparing acyclovir and famciclovir found that famciclovir was as effective as acyclovir in treating acute uncomplicated herpes zoster, with no significant difference in time taken for full crusting, complete healing of lesions, or loss of acute pain 4.
- A meta-analysis found that 800 mg of acyclovir five times a day can improve the effective rate, shorten the blister stopping time, relieve pain faster, and shorten the scabbing time without increasing the adverse reaction rate 5.
Comparison with Other Antiviral Drugs
- Valaciclovir has been shown to be at least as effective as acyclovir in controlling the symptoms of acute herpes zoster, and it alleviates zoster-associated pain and post-herpetic neuralgia significantly faster than acyclovir 3.
- Famciclovir has been found to be as effective as acyclovir in treating acute uncomplicated herpes zoster, with a better safety profile and a more convenient dosage regimen 4.
- The varicella zoster virus vaccine has been shown to decrease the incidence of herpes zoster and is approved for adults 50 years and older 6.
Treatment Guidelines
- The Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices recommends the varicella zoster virus vaccine for adults 60 years and older, except for certain immunosuppressed patients 6.
- Treatment of herpes zoster is focused on symptom control and includes antiviral drugs like acyclovir, valacyclovir, or famciclovir, ideally within 72 hours of the development of the rash 6.