According to a German study some popular new drugs for rheumatoid arthritis could increase the risk of shingles. The drugs of a class called TNF-alpha blockers (anti-tumour necrosis factor alpha) were found to nearly double the risk of herpes zoster, better known as shingles, among rheumatoid arthritis sufferers.

Shingles is a skin disease which produces sore, itchy blisters and is the reactivation of the same virus infection that causes chickenpox. The virus usually remains in the body after the chickenpox and returns in the form of shingles usually after the age of 50. Pain, itching or tingling of an area of skin on one side of the body or face indicates the start of shingles. It later develops into a rash and many people continue to suffer chronic nerve pain once the rash has subsided.

The study was conducted by the team at the Rheumatism Research Centre in Berlin who analyzed data from 5,040 patients on different forms of treatment. They noted 86 outbreaks of shingles which were triggered by the virus Herpes zoster in 82 patients and 39 of these were found to be related to treatment with the anti-TNF drugs adalimumab and infliximab.

A protein therapy, Etanercept as well as conventional disease modifying anti-rheumatic drugs were linked with 23 and 24 cases respectively. The researchers noted that after adjusting the age of the patient, the severity of their illness and their use of steroid hormone therapies, the risk of patients on anti-TNF were almost double.

Anja Strangfeld, MD, of the German Rheumatism Research Center in Berlin said the drugs Humira, Kineret, and Remicade are all biologic agents called monoclonal antibodies and they increased shingles risk by about 80% while Enbrel, a slightly different TNF alpha blocker did not.

"We compared these different types of TNF inhibitor with conventional disease-modifying anti-rheumatic drugs and we found there is an increased risk of herpes zoster in patients treated with the monoclonal antibodies," said Strangfeld .The risk from Enbrel was not significant.

Strangfeld said doctors should be on the lookout for shingles in patients who were being treated with these drugs. "Based on our data, we recommend careful monitoring of patients treated with monoclonal anti-TNF-alpha antibodies for early signs and symptoms of Herpes zoster," they wrote in the Journal of the American Medical Association.

Richard J. Whitley, MD, professor of pediatrics, microbiology, medicine, and neurosurgery at the University of Alabama, Birmingham said "It's pretty clear that if you have had previous zoster and take these anti-TNF monoclonal antibodies, you are going to reactivate it. I think it is reasonable to go with Enbrel for patients with prior zoster."

Although the risk of shingles increased with these drugs it was not clear if they raise the risk of severe shingles and Whitley pointed out there were relatively few cases of postherpetic neuralgia, the shingles side effect of lasting pain. The reassuring fact is that there is a vaccine for shingles and as the vaccine uses a live virus, people can't get the vaccine while taking anti-TNF drugs, which suppress the immune system.

The Strangfeld studies, and Whitley's editorial commentary, are in the Journal of the American Medical Association.