blood levels similar to intravenous acyclovir. For treating shingles, it is commonly administered in a dose of 1000 mg three times daily for seven days. When compared with acyclovir, valacyclovir shows slightly higher effectiveness in decreasing pain severity of the shingles rash, as well as the duration of post-herpetic neural- gia. Dose adjustments may be necessary in patients with severe renal insufficiency because of its renal clearance. Valacyclovir is a generic medication, associated with the brand name Valtrex (Al- brecht & Levin, 2021). Famciclovir is another antiviral in the same drug class as acyclovir and valacyclovir. It has the best bioavailability of all three agents and has a longer half-life when compared with acyclovir. In treat- ing shingles, it is commonly administered at a dose of 500 mg three times daily for seven days. Famciclovir is a generic medi- cation associated with the brand name Famvir (Albrecht & Levin, 2021). Selecting an appropriate antiviral agent should be individualized, based on patient-specific factors. Dosing schedule and cost are often considered in the selection process. All three antiviral med- ications are typically well-tolerated; adverse effects include nau- sea, vomiting, headache, dizziness, and abdominal pain (Albrecht & Levin, 2021). Patients who have been treated long term with acyclovir, as well as immunocompromised patients with persistent infections, are at an increased risk of developing resistance to acy- clovir and may require alternative antiviral therapy (Shiraki et al., 2021). Pain associated with shingles can often be treated with over-the- counter medications such as acetaminophen or non-steroidal an- ti-inflammatory agents. Stronger medications may be necessary in some patients; opiates and drugs used to treat neuropathic pain, such as gabapentin, can be used. Despite variable results from clinical trials, prescribers may consid- er using oral corticosteroids to treat pain associated with shingles. Corticosteroids, such as prednisone, are thought to reduce nerve inflammation in shingles which leads to pain, and potentially re - duce residual damage to the nerves involved. When used in con- junction with antivirals, prednisone has not been shown to reduce shingles-associated pain. Since steroids can induce immunosup- pression, which can lead to the development of shingles, their
use should be limited to patients over the age of 50, since these patients are at a higher risk of developing post-herpetic neuralgia. Patient-specific factors should also be considered to determine if a patient is a candidate for corticosteroid treatment (Albrecht & Levin, 2021; Kowalsky & Wolfson, 2019). Adequate skin care is recommended in shingles patients. Lotions, such as calamine, as well as wet compresses and colloidal oatmeal baths can often relieve itching. Opened blisters that are showing signs of bacterial infection may require topical or oral antibiotics. Patients should be advised against scratching blisters, if possi- ble, since the fluid in blisters is contagious, and scratching creates wounds that could become infected or leave scars. Shingles pa- tients should also avoid direct contact with others who have un- known immunity to chicken pox, particularly immunosuppressed patients and pregnant women. Covering the rash and washing hands often can decrease the risk of spreading the varicella zoster virus (Albrecht & Levin, 2021; CDC, 2019). Patient counseling Patients with shingles should be reminded about the contagious nature of the fluid contained in shingles blisters. They should be reminded to cover the rash and avoid scratching or touching blisters. Washing hands thoroughly after contact with lesions is recommended to prevent spreading varicella zoster virus. Patients with shingles should be counseled to avoid contact with immu- nocompromised people, such as pregnant women, premature infants, and those with weak immune systems. Contact should be avoided until the rash is no longer producing new blisters and crusts or scabs have developed (CDC, 2019). Patients are often concerned about their ability to return to work after developing shingles. Return to work often depends on where the patient works and where the rash is located. If the blisters are located in an area that can be covered with bandages or clothing, patients can typically return to work when they are feeling well. Patients with blisters located on the face or an area that cannot be covered should not return to work until the blisters have crusted over, which commonly takes 7 to 10 days. Patients who work in childcare or healthcare settings should consult their employer to determine when it is safe to return to work (Albrecht, 2019).
VACCINATIONS TO PREVENT SHINGLES
At this time, only one vaccine is available in the United States to prevent reactivation of latent varicella zoster virus that leads to shingles. In October 2017, the FDA approved Shingrix for use in patients 50 and older. It has replaced the use of Zostavax, which is no longer available in the United States (GlaxoSmithKline, 2021). Shingrix Shingrix is now available for prevention of shingles caused by varicella zoster virus reactivation. It is a recombinant, adjuvanted vaccine for intramuscular injection and is FDA-approved for use in patients 50 and older (GlaxoSmithKline, 2021). Shingrix is not a live vaccine; it contains varicella zoster virus an- tigen to trigger a targeted immune response and is combined with an adjuvant in order to enhance the immune response (GlaxoSmithKline, 2021). Adjuvanted vaccines are thought to trig- ger a more robust immune response, creating a stronger immune protection (CDC, 2020). Efficacy The manufacturer of Shingrix, GlaxoSmithKline, conducted two studies to assess its efficacy before FDA approval. The first study was an age-stratified, randomized, placebo-controlled study of over 14,000 subjects that assessed vaccine efficacy in subjects ages 50 and older. The study excluded those who were immuno- compromised, had a previous history of shingles, those who were vaccinated against shingles or varicella, and those with significant comorbid conditions with an expected survival of less than four years. After following subjects for an average of three years, the study found that two doses of Shingrix resulted in a significant reduction – 97.2% – in the risk of developing shingles when com-
pared with a placebo. The study also found a significant reduction in post-herpetic neuralgia with Shingrix, as no cases developed in the vaccinated group as compared with 18 cases in the placebo group (GlaxoSmithKline, 2021). The second pre-approval study was a randomized placebo-con- trolled study of over 13,000 subjects that assessed vaccine effi - cacy in patients ages 70 and older. After an average follow-up of 3.9 years, vaccine efficacy was noted to be approximately 85% in the fourth year after vaccination in this older patient population. Shingrix was also associated with lower rates of post-herpetic neuralgia in this age group when compared with placebo, with four cases reported in the vaccine group and 28 cases reported in the placebo group (GlaxoSmithKline, 2021). When data were pooled between the two studies for patients ages 70 and older, researchers found a 91.3% reduction in the risk of developing shingles in those who have received two doses of Shingrix (GlaxoSmithKline, 2021). Since data are not currently available to evaluate the long-term efficacy of Shingrix vaccination, modeled data based on the first four years of clinical trial data, as well as expert opinion, was used to assess long-term efficacy. Modeled data show that in adults over the age of 50, efficacy would wane to zero 19 years after vaccination, assuming vaccinated patients received two doses of Shingrix at recommended dosing intervals (Dooling et al., 2018). Contraindications and precautions Shingrix should not be administered to patients with a history of a severe allergic reaction to a previous dose of Shingrix or to any component of the vaccine. Patients who have a current episode
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