The incidence of postherpetic neuralgia in patients with herpes zoster in the context of combination therapy with gabapentin and valaciclovir
Patients with shingles, who are at increased risk of developing postherpetic neuralgia, should receive combination therapy with the appropriate antiviral drug and gabapentin at the onset of the disease.
Postherpetic neuralgia (PHN) is a painful, painful and often debilitating complication of an acute infection caused by the herpes zoster virus. This complication is characterized by an intense neuropathic pain syndrome. Patients generally describe the pain as continuous bouts of acute, throbbing, or burning pain, which often keep them awake at night. Post-herpetic neuralgia due to inflammatory nerve damage during infection can persist for months or even years, is difficult to cure and causes a high incidence of disease. Risk factors for developing PHN include age over 50, severe or severe skin manifestations of infection, worsening pain associated with acute viral infection, and severe prodromal pain [1]. Acyclovir and its analogs (valaciclovir, famciclovir) accelerate the resolution of herpes lesions of the skin and pain by reducing the number of viruses. However, it remains unclear whether these antiviral drugs can reduce the frequency or actual severity of PHN [2, 3, 4]. At the same time, the use of the varicella-zoster vaccine can reduce the incidence of PHN by approximately 66.5% [5].
Tricyclic antidepressants and anticonvulsant gabapentin can reduce the severity of pain in PHN, but there is a limited amount of data supporting their use in the acute phase of shingles to prevent the development of PHN [6, 7]. To answer this very important question, Dr. Lapolla and his colleagues conducted an open study that compared the incidence of PHN after treatment with 2 drugs (valacyclovir and gabpentine, which was used at a dose of 300 mg per day with a possible increase in dose up to a maximum of 1200 mg orally 3 once a day with satisfactory tolerance). The study included 133 patients with shingles and mild to severe pain (mean age 64.6 years, 67% of women, 82% of the Caucasian). Since the onset of the disease, all patients have received 2 drugs - valaciclovir (1000 mg orally 3 times a day for 7 days) and gabapentin (300 mg per day with weekly titration with satisfactory tolerance up to one dose daily maximum of 3600 mg, divided into 3 doses). Gabapentin has been withdrawn in patients who have not experienced even mild pain for more than a week. The results of the study are as follows:
Thus, in this study, although there was no control group, strong evidence was obtained that the simultaneous administration of valaciclovir and gabapentin in the acute phase of herpes zoster significantly reduced the incidence and the severity of PHN. The main limitations of this study were the absence of a control group (the appointment of valaciclovir only without gabapentin), which led the researchers to compare with historical control. However, including a control group in the future can be ethically complicated, as rejection of the use of gebapentin can significantly increase the risk of developing PHN in patients in the high risk (for example, elderly patients with severe herpes zoster). However, you can try to compare the effectiveness of gabapentin with amitriptyline, a tricyclic antidepressant, which can also reduce the incidence of PHN.
Therefore, patients in the group at increased risk of developing postherpetic neuralgia (the elderly, patients with severe herpes zoster) should be offered combination therapy, including the appropriate antiviral medication (e.g. valaciclovir) and gabapentin, in the absence of specific contraindications for the use of gabapentin. Dermatologists and other doctors who treat these types of patients should be familiar with the correct dosing schedule and the possible side effects of the medication that occur while using gabapentin, as this medication can in rare cases cause side effects. severe (for example, seizures or Stevens syndrome). Johnson).