What is the recommended management of shingles (herpes zoster) in an adult, including antiviral therapy, pain control, and vaccination?

Management of Herpes Zoster (Shingles) in Adults

Start oral valacyclovir 1000 mg three times daily or famciclovir 500 mg every 8 hours for 7 days within 72 hours of rash onset, combined with stepped analgesia beginning with acetaminophen, and strongly recommend Shingrix vaccination for all adults ≥50 years to prevent future episodes. 1, 2

Antiviral Therapy: First-Line Treatment

Valacyclovir and famciclovir are preferred over acyclovir due to superior bioavailability and more convenient dosing schedules, though all three reduce acute pain intensity and accelerate cutaneous healing when initiated within 72 hours. 1, 3

• Valacyclovir 1000 mg three times daily for 7 days is the preferred first-line oral regimen, producing plasma acyclovir levels equivalent to intravenous administration. 2, 4
• Famciclovir 500 mg every 8 hours for 7 days offers comparable efficacy to valacyclovir with similar outcomes. 2, 5
• Acyclovir 800 mg five times daily for 7 days remains an option but requires more frequent dosing and has lower bioavailability. 5, 3
• Dose reduction is mandatory in patients with creatinine clearance <50 mL/min to avoid toxicity, particularly critical in older adults with reduced renal function. 2

Severe Disease Requiring IV Therapy

Intravenous acyclovir 10 mg/kg every 8 hours for 21 days is indicated for central nervous system complications (meningoencephalitis, myelitis), disseminated disease, or immunocompromised patients with signs of visceral involvement. 2, 3

Pain Management: Stepped Analgesic Approach

Mild to Moderate Pain

• Acetaminophen 3000-4000 mg/day in divided doses is the first-line analgesic due to its favorable safety profile in older adults. 1, 2
• NSAIDs should be used with extreme caution in elderly patients, requiring routine monitoring of gastrointestinal toxicity, renal function, blood pressure, and drug interactions due to risks of GI bleeding, renal impairment, hypertension, and heart failure. 1, 2

Moderate to Severe Pain

Opioids should be initiated at low doses with gradual titration, using scheduled dosing for continuous pain rather than as-needed administration. 1, 2

• Anticipate and proactively manage opioid-related adverse effects including sedation, cognitive impairment, falls, and constipation—particularly problematic in older adults. 1, 2
• Consider prophylactic bowel regimens when prescribing opioids to prevent constipation. 6

Prevention of Postherpetic Neuralgia (PHN)

Initiate gabapentin during the acute phase (starting 100-300 mg at bedtime, titrating to 300-600 mg three times daily as tolerated) alongside conventional analgesics to reduce PHN risk. 1, 2

• Nortriptyline 10-25 mg at bedtime with slow titration is preferred over amitriptyline in older adults due to lower anticholinergic burden. 1, 2
• Early antiviral treatment with valacyclovir or famciclovir represents the only proven pharmacologic intervention to prevent PHN development. 7, 4

Topical Therapies for Localized Pain

Lidocaine 5% patches (up to 3 patches for 12 hours daily) provide safe, non-systemic pain relief with no documented systemic absorption or toxicity, making them exceptionally valuable for elderly patients on multiple medications or those with renal impairment. 1, 2

• The 5% prescription strength is significantly more effective than 4% over-the-counter formulations or lidocaine gel/cream. 1
• Compounded amitriptyline 1-2% with ketamine 0.5% applied up to three times daily serves as an alternative if lidocaine fails. 1
• Capsaicin topical therapy may benefit select patients but is often poorly tolerated. 1, 6

Medications to Avoid in Older Adults

Never prescribe muscle relaxants (cyclobenzaprine, carisoprodol) or benzodiazepines due to significant anticholinergic effects, sedation, cognitive impairment, and dramatically increased fall risk. 1, 2

Corticosteroid Use: Generally Not Recommended

Systemic corticosteroids are not routinely recommended for herpes zoster in older adults due to heightened risks of hyperglycemia, hypertension, glaucoma, and peptic ulcer disease. 2

• If absolutely necessary in specific acute situations, prednisone 0.5-1 mg/kg daily for maximum 10-14 days may be considered, though evidence for benefit in preventing PHN is inconsistent. 2, 4
• When corticosteroids are used, they must always be combined with antiviral therapy, never administered alone. 8

Vaccination: The Most Effective Prevention Strategy

Shingrix (recombinant zoster vaccine, RZV) is strongly recommended for all adults ≥50 years, demonstrating 97.2% efficacy against herpes zoster in adults ≥50 years, 91% efficacy in those ≥70 years, and 89% efficacy against PHN, with protection persisting >83% for up to 8 years. 1, 2, 8

Shingrix vs. Zostavax

Shingrix is vastly superior to Zostavax (live attenuated vaccine, ZVL) with 97% efficacy compared to 70% for Zostavax, which declines to only 14.1% within 10 years. 5, 8

• Shingrix is safe for immunocompromised patients because it contains only viral glycoprotein E with adjuvant AS01B, eliminating theoretical risk of disease from live attenuated virus. 5, 8
• Two-dose series: administer second dose 2-6 months after the first (minimum 4-week interval if necessary). 8
• Vaccinate even patients with prior herpes zoster history, as the vaccine prevents recurrence and complications. 2, 7

Special Consideration: Patients with History of Herpetic Keratitis

Use Shingrix exclusively (not Zostavax) in patients with history of herpetic keratitis, administering the first dose when keratitis has been completely quiescent for at least 2-3 months. 8

• If reactivation occurs post-vaccination, standard treatment with oral antivirals and topical corticosteroids (always combined, never corticosteroids alone) is generally effective. 8
• The benefits of vaccination dramatically outweigh the rare risk of reactivation, especially given Shingrix's 97.2% efficacy in preventing new ocular episodes. 8

Special Populations

Immunocompromised Patients

Recombinant zoster vaccine (Shingrix) is recommended for adults ≥18 years who are or will be immunodeficient due to disease or therapy, as it poses no risk from live virus. 5

• Monitor closely for signs of cutaneous or visceral dissemination; if present, switch immediately to intravenous antiviral therapy. 3
• Oral antivirals benefit immunocompromised patients with uncomplicated herpes zoster. 3

Pregnant Women

Acyclovir is FDA Category B; intravenous acyclovir should be considered for serious viral-mediated complications like pneumonia, though routine oral use is not recommended. 5