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Managing Shingles in Older Adults

March 14, 2014
Citation: 

Annals of Long-Term Care: Clinical Care and Aging. 2014;22(3):25-27.

Herpes zoster, also known as shingles, develops when the varicella zoster virus (VZV) is reactivated in the dorsal ganglia and migrates to adjacent sensory dermatomes, causing a rash and pain. An estimated 90% of adults in the United States carry VZV, and the risk of reactivation increases with age. Vaccination among older adults is key to preventing serious VZV-related complications, such as postherpetic neuralgia (PHN). Many older adults who neglect getting the vaccine may eventually become institutionalized for these complications, compromising patient quality of life and increasing  healthcare burden and costs.
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Annals of Long-Term Care® (ALTC) had the opportunity to discuss shingles with geriatric pharmacist Kenneth Cohen, PharmD, PhD, CGP, associate professor, Department of Pharmacy and Health Outcomes, Touro College of Pharmacy, New York, NY. ALTC asked him to review the evidence-based recommendations for vaccination and management of shingles-related pain in complex older patients, as well as discuss some of the issues under investigation, such as management of secondary infections and use of novel treatments.

ALTC: What are the current evidence-based recommendations for shingles vaccination?

Cohen: A live attenuated VZV vaccine (Zostavax) is available to prevent reactivation of VZV in adults older than 60 years. Oxman and colleagues demonstrated that the vaccine significantly reduced the incidence of herpes zoster, the burden of the illness on quality of life, and incidence of associated PHN.

The current recommendations for administration of herpes zoster vaccine published by the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices advise routine vaccination with one dose of zoster vaccine in individuals older than 60 years. Individuals reporting a previous episode of zoster can be vaccinated if there are no contraindications. It is not necessary to obtain a history of chickenpox or to test for varicella immunity.

It is interesting to note that the herpes zoster vaccination is not recommended for individuals of any age who have received the varicella vaccine; however, since vaccination against varicella did not begin until 1995 in the United States, the geriatric population is not impacted. Patients taking antivirals, such as acyclovir, famciclovir, or valacyclovir, should discontinue these medications at least 24 hours prior to administration of zoster vaccine, if possible, and should not be restarted until at least 14 days after the vaccination. These agents may interfere with replication of the live VZV-based zoster vaccine.

What are the major goals and considerations for treating shingles in older adults?

Goals of treatment include quicker healing of skin lesions, reducing the risk of complications, and decreasing the risk of viral dissemination. These goals are best achieved through the use of antiviral drugs.

Antivirals must be started immediately, and any prescribed ophthalmic steroids should be reduced. If ophthalmic symptoms occur, an immediate referral to an ophthalmologist is key. It is also desirable to limit the severity and duration of acute and chronic pain and to differentiate therapy between the two.

In the elderly, you need to monitor for many different complications. In the “walking well” elderly patient, it is not uncommon to see constipation, confusion, and instability secondary to narcotic analgesic use. Also, monitoring for anticholinergic effects of tricyclic antidepressants (TCAs) is important, as is monitoring for any interactions with patients’ regular medication regimens. Adverse effects may interfere with their normal activities of daily living and result in their requiring a higher level of care.

For the long-term care patient, participation in regular care programs could be disrupted, and there could be an increase in instability—including vertigo in both the prodromal stage and as a long-term complication—resulting in increased risk for falls. Careful titration of pain medications is important to balance the need for analgesia with the risks of adverse effects, such as lethargy and constipation, from these drugs.

What are the considerations before prescribing an oral antiviral to an older patient?

The oral antiviral agents acyclovir, valacyclovir, and famciclovir have been shown to reduce the severity and duration of VZV infection. These agents are administered systemically. Topical antiviral agents are ineffective and are not recommended.

Early antiviral intervention provides a greater likelihood of a clinical response. Most trials enrolled patients within 72 hours of the onset of symptoms, but acyclovir is most effective when administered within 48 hours of the onset of the VZV rash.

Acyclovir is considered the mainstay of treatment; however, its clinical use in the elderly is limited by its multiple dosing schedule (five times daily) and less favorable pharmacokinetic profile when compared with valacyclovir and famciclovir. Valacyclovir is the oral prodrug of acyclovir and is only required to be administered three times daily. Studies indicate that valacyclovir accelerated the resolution of herpes zoster–associated pain when compared with acyclovir. However, the rash subsided at the same rate.

Famciclovir has a longer half-life than acyclovir and allows three times daily dosing, but the drugs are equivalent in efficacy and speed of resolution. Foscarnet is useful in acyclovir-resistant viruses. It appears to be useful in the HIV population but has toxic effects on the kidneys and gastrointestinal tract.

 

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