Prescription of antiviral therapy after herpes zoster in general practice: who receives therapy?

BACKGROUND: Antivirals can accelerate rash healing during an acute zoster episode and can limit the severity and duration of pain. Their use within 7 days of rash onset is recommended among specific patient groups. AIM: To describe antiviral prescription patterns and patient characteristics associated with antiviral receipt after zoster diagnosis. DESIGN AND SETTING: Descriptive study and risk factor analysis using electronic healthcare records from UK general practice. METHOD: Incident adult zoster cases occurring between 2000 and 2011 were identified in the General Practice Research Database. Therapy records were searched for antiviral prescriptions of aciclovir, famciclovir, or valaciclovir within 7 days of zoster diagnosis. The proportion of incident zoster cases receiving antivirals was calculated and multivariable logistic regression used to assess associations between patient characteristics and antiviral use. RESULTS: Of 142 216 incident zoster cases 58.1% received an antiviral prescription. The majority (69.0%) were aciclovir. The proportion receiving antiviral prescriptions increased with age up to 65 years, then declined to 56.8% among patients aged ≥85 years. Being female and of higher socioeconomic status were associated with higher antiviral receipt. Antivirals were more commonly prescribed to immunosuppressed patients with herpes zoster (odds ratio 1.27; 95% CI = 1.22 to 1.33), however they were not given routinely to this patient group. CONCLUSION: Antiviral therapies for zoster are under-prescribed in UK general practice even among groups, such as immunosuppressed and older individuals, for whom guidelines recommend treatment. Patients may present too late to receive treatment or physicians may decide that antivirals are not essential treatment. Consideration could be given to reviewing the guidelines.