14-day famciclovir treatment significantly reduces the incidence of postherpetic neuralgia in elderly patients with herpes zoster

What is known and objective: Pain is the main symptom of herpes zoster (HZ), whilst postherpetic neuralgia (PHN) is a long-term unbearable pain, which seriously affects the quality of life of patients and is also the most intractable problem for clinicians. Early antiviral treatment is considered as a key measure to reduce acute pain and PHN. Nevertheless, most patients still have long-term pain after 7 days of antiviral treatment, and some patients will develop PHN. This study aimed to investigate whether prolonged duration of antiviral therapy could reduce HZ acute pain and the occurrence of PHN.

Methods: The outpatient data of HZ patients over 50 years old who visited the Dermatology Department from January 2016 to May 2018 were retrospectively analysed. According to the different courses of treatment of famciclovir (FCV), the patients were divided into 7-day FCV group and 14-day FCV group. The numerical rating scale (NRS) score at the first visit and on the 7th, 14th and 21st days after the start of treatment, the adverse drug reactions and the incidence of PHN were compared between the two groups.

Results: A total of 219 patients were involved in the analysis. For acute pain control, the 14-day FCV group was better than the 7-day FCV group. For patients with mild initial pain, there was no significant difference in NRS between the two treatments. For patients with moderate-to-severe initial pain, the NRS in the 14-day FCV group was significantly lower than that of the 7-day FCV group on the 14th and 21st days after starting treatment. PHN occurred in patients with moderate-to-severe initial pain, and the incidence was significantly lower in the 14-day FCV group than in the 7-day FCV group. There was no significant difference in the number of adverse reactions between the two groups.

What is new and conclusion: Compared with the traditional 7-day antiviral therapy, the 14-day course of FCV can reduce the acute pain and the incidence of PHN in elderly patients with HZ, especially in patients with moderate to severe initial pain. Prolonging the course of medication did not increase the side effects.