How should shingles (herpes zoster) be managed in adults, including antiviral therapy, pain control, and vaccination recommendations?

Management of Shingles (Herpes Zoster) in Adults

Antiviral Therapy

Initiate antiviral therapy within 72 hours of rash onset to reduce acute pain duration and rash severity. 1

• Valacyclovir 1000 mg three times daily for 7 days or famciclovir 500 mg every 8 hours for 7 days are preferred over acyclovir due to superior bioavailability and more convenient dosing schedules. 1

• These agents are particularly advantageous in older adults where medication adherence is critical. 1

• Dose adjustments are necessary in patients with renal impairment—monitor creatinine clearance before initiating therapy. 1

• Even if the 72-hour window has passed, antiviral therapy may still benefit patients with new lesion formation, ophthalmic involvement, or immunocompromised status. 2

Pain Management: Stepped Analgesic Approach

Begin with acetaminophen for mild pain, escalate to opioids for moderate-severe pain, and add gabapentin or nortriptyline early to prevent postherpetic neuralgia (PHN). 1

Mild to Moderate Pain

• Acetaminophen 3000-4000 mg/day in divided doses is first-line due to its favorable safety profile in older adults. 1

• Avoid NSAIDs in elderly patients whenever possible—they carry significant risks of gastrointestinal bleeding, renal dysfunction, hypertension exacerbation, and heart failure. 1

• If NSAIDs are unavoidable, use the lowest effective dose for the shortest duration with routine monitoring of renal function, blood pressure, and gastrointestinal symptoms. 1

Moderate to Severe Pain

• Initiate low-dose opioids (e.g., oxycodone 5 mg every 4-6 hours as needed) and titrate gradually based on response. 1

• Use scheduled dosing rather than as-needed for continuous or frequent pain. 1

• Anticipate and prophylactically manage opioid side effects: prescribe a stimulant laxative for constipation, monitor for sedation and cognitive impairment, and assess fall risk. 1

Adjuvant Therapy to Prevent PHN

• Gabapentin should be started during the acute phase, beginning at 100-300 mg at bedtime and titrating to 300-600 mg three times daily as tolerated. 1

• Nortriptyline 10-25 mg at bedtime is preferred over amitriptyline in older adults due to lower anticholinergic burden; titrate slowly. 1

• These agents reduce the risk of developing PHN, the most debilitating long-term complication of shingles. 1, 3

Topical Therapies

• Lidocaine 5% patches (up to 3 patches for 12 hours daily) are highly effective for localized neuropathic pain with negligible systemic absorption, making them exceptionally safe for elderly patients on multiple medications. 1

• The 5% prescription strength is superior to 4% over-the-counter formulations and far more effective than lidocaine gel or cream. 1

• Capsaicin topical therapy has moderate evidence but is often poorly tolerated due to burning sensations. 1

Medications to Avoid in Older Adults

• Never use muscle relaxants (cyclobenzaprine, carisoprodol) due to severe anticholinergic effects and fall risk. 1

• Avoid benzodiazepines due to sedation, cognitive impairment, and increased fall risk. 1

Vaccination Recommendations

All adults aged ≥50 years should receive the 2-dose Shingrix (recombinant zoster vaccine) series, regardless of prior shingles history or previous Zostavax vaccination. 4

Standard Dosing Schedule

• Administer the second dose 2-6 months after the first dose (minimum interval 4 weeks if necessary). 4

• For immunocompromised adults aged ≥18 years, use a shortened schedule with the second dose at 1-2 months after the first. 4

Superiority of Shingrix Over Zostavax

• Shingrix demonstrates 97.2% efficacy in preventing herpes zoster in adults ≥50 years, compared to Zostavax's initial 51-70% efficacy that declines to only 14.1% by year 10. 4, 5, 6

• Shingrix maintains efficacy above 83.3% for at least 8 years with minimal waning. 4

• Shingrix is safe for immunocompromised patients (non-live recombinant vaccine), while Zostavax is contraindicated in this population. 4, 7

Vaccination After Shingles Episode

• Vaccinate once acute symptoms have resolved, typically waiting at least 2 months after the episode. 4

• Having shingles once does not provide reliable protection—the 10-year cumulative recurrence risk is 10.3%. 4

Revaccination for Previous Zostavax Recipients

• All adults who received Zostavax should receive the full 2-dose Shingrix series, administered at least 2 months after the last Zostavax dose. 4

• This recommendation applies even to those vaccinated years ago, as Zostavax provides inadequate long-term protection. 4

Special Populations

• Patients on JAK inhibitors (e.g., tofacitinib) should ideally complete the full 2-dose Shingrix series before starting therapy to maximize immune response. 4

• Patients on low-dose glucocorticoids (<10 mg/day prednisone equivalent) can safely receive Shingrix without adversely impacting vaccine response. 4

• Patients with herpetic keratitis history should receive Shingrix (not Zostavax) when keratitis has been completely quiescent for at least 2-3 months. 7

Common Side Effects

• Injection-site reactions (pain, redness, swelling) occur in 9.5% of recipients (grade 3) versus 0.4% with placebo. 4

• Systemic symptoms (myalgia, fatigue, fever) occur in 11.4% versus 2.4% with placebo, typically resolving within 4 days. 4

• No serious safety concerns have been identified in large clinical trials. 4

Prevention as the Most Effective Strategy

Vaccination with Shingrix is the single most effective intervention for preventing both herpes zoster and its complications, including PHN. 1, 7

• The 97.2% efficacy of Shingrix far exceeds the effectiveness of any treatment for established disease or PHN. 1, 5

• Once PHN develops, current treatments offer only limited benefit (<50% of patients achieve 50% pain relief), making prevention paramount. 3