From the Guidelines
Given the patient's tolerance issues with Famvir, alternative antiviral medications such as valacyclovir or acyclovir should be considered for the treatment of shingles. The patient can tolerate Famvir despite nausea and vomiting, but it is crucial to consider alternatives that may be better tolerated. According to the guidelines, valacyclovir (Valtrex) 1 gram three times daily or acyclovir 800 mg five times daily for 7-10 days are effective alternatives 1. These medications work through the same mechanism as famciclovir by inhibiting viral DNA synthesis.
Some key points to consider in the treatment of shingles include:
- Starting treatment as soon as possible after rash onset, ideally within 72 hours, to maximize effectiveness in reducing the severity and duration of shingles and to lower the risk of postherpetic neuralgia 1.
- Managing nausea with anti-nausea medications such as ondansetron 4-8 mg as needed, which can be prescribed alongside the antiviral to manage nausea.
- Considering pain management options such as acetaminophen, NSAIDs, or in more severe cases, gabapentin or pregabalin, which may be helpful in reducing discomfort associated with shingles.
It is essential to note that the treatment should continue at least until all lesions have scabbed, as recommended by the guidelines 1. The choice of antiviral medication should be based on the patient's tolerance and the severity of the disease. In this case, since the patient can tolerate Famvir despite nausea and vomiting, it is crucial to weigh the benefits and risks of continuing with Famvir versus switching to an alternative medication. However, valacyclovir or acyclovir are recommended as first-line treatments for uncomplicated herpes zoster 1, and their use should be considered in patients who can tolerate them.
From the FDA Drug Label
The most common adverse events reported in at least 1 indication by greater than 10% of adult patients treated with famciclovir are headache and nausea. Nausea 12.5 Vomiting 4.8
The patient can tolerate Famvir with nausea and vomiting for treatment of shingles, as these are common adverse events reported in clinical trials, with nausea occurring in 12.5% and vomiting in 4.8% of patients 2.
From the Research
Tolerability of Famvir
- The patient's ability to tolerate Famvir (famciclovir) for the treatment of shingles, despite experiencing nausea and vomiting, is supported by studies that show Famvir to be well-tolerated with a tolerability profile similar to that of placebo and aciclovir 3.
- Famvir is reported to be effective in treating immunocompetent patients with acute herpes zoster (shingles) caused by varicella zoster virus (VZV), with therapeutic efficacy similar to that of oral aciclovir (acyclovir) in attenuating the acute signs and symptoms of infection 3.
- A systematic review and meta-analysis of high-quality randomized controlled trials found that famciclovir was superior to aciclovir in reducing the risk of pain associated with herpes zoster, with a 46% reduction in risk of pain at 28-30 days 4.
Comparison with Other Antivirals
- Valaciclovir, another antiviral medication, has been shown to be at least equivalent to, and better in certain parameters than, aciclovir, and appears to have similar efficacy to famciclovir 500 mg 3 times daily 5.
- A review of antiviral therapy for herpes labialis, genital herpes, and herpes zoster found that oral acyclovir, valacyclovir, and famciclovir are efficacious and safe for the treatment of the first episode and recurrent genital herpes, and are useful as suppressive therapy for individuals with frequent genital herpes recurrences 6.
- High doses of oral acyclovir, valacyclovir, and famciclovir have been shown to speed the healing of herpes zoster, and data suggests that these agents also decrease associated acute and chronic pain in people of 50 years of age or older 6.
Efficacy and Safety
- The efficacy of famciclovir for the treatment of herpes zoster has been confirmed and extended by follow-up studies in herpes zoster ophthalmicus, in Japanese patients, and in the wider primary care setting 5.
- Famciclovir is reported to be safe and effective in the therapy of patients with herpes simplex and herpes zoster, and may be useful in other viral infections 7.
- The adverse events profile of famciclovir is similar to that seen with aciclovir or valaciclovir, with nausea and headache being the most commonly reported adverse events 5.