A new study suggests that there is an association between medications known as monoclonal anti-tumour necrosis factor a (TNF-a), which are used for treating rheumatoid arthritis, and an increased risk for herpes zoster (shingles), the painful infection characterized by blisters.
Appearing in the journal JAMA, a research article says that there has been evidence from some studies that patients treated with anti-TNF-a agents are at an increased risk of bacterial infections, but little is known about the risk of viral infections, such as herpes zoster, in patients with rheumatoid arthritis receiving these types of medications.
According to background information in the article, Herpes zoster is one of the most common adverse events reported in clinical trials of anti-TNF-a agents.
Dr. Anja Strangfeld, of the German Rheumatism Research Center in Berlin, says that patients with rheumatoid arthritis are at increased risk of herpes zoster as compared with the general population.
During the study, Strangfeld's team investigated the association of various rheumatoid arthritis treatments, including anti-TNF-a therapy, with the risk of herpes zoster.
The researchers analysed data from patients who began treatment with adalimumab or infliximab (monoclonal anti-TNF-a antibodies), etanercept (a fusion protein), the monotherapeutic agent anakinra, or when patients changed conventional disease-modifying anti-rheumatic drug (DMARD).
Rheumatologists assessed treatment, clinical status and adverse events at fixed points during follow-up (of up to three years). A total of 5,040 patients were included in the analysis.
The researchers observed that there were 86 cases of herpes zoster among 82 patients.
According to them, 39 occurrences could be attributed to treatment with anti-TNF-a antibodies.
The researchers found a significant association between herpes zoster and treatment with the monoclonal anti-TNF-a antibodies infliximab and adalimumab, although this risk was lower than the threshold for clinical significance.
There seemed to be no significant association between herpes zoster and treatment with etanercept, or anti-TNF-a treatment as a class.
The researchers found a significantly higher risk of developing herpes zoster for patients of older age and for treatment with glucocorticoids, steroid hormones that are widely used as anti-inflammatory medications.
"Based on our data, we recommend careful monitoring of patients treated with monoclonal anti-TNF-a antibodies for early signs and symptoms of herpes zoster," the authors conclude.