Rheumatism treatment may raise risk of shingles

The use of Humira (generic name: adalimumab) or Remicade (generic name: infliximab) to treat rheumatoid arthritis may slightly increase the risk of shingles, researchers report in the Journal of the American Medical Association.

Shingles is a viral infection caused by the varicella zoster virus, the same one that causes chicken pox. There is no cure for shingles, which causes a painful, blistering rash. After a person has had chicken pox, the virus remains dormant in the body, and years later can reactivate as shingles.

Humira and Remicade are drugs that work by blocking a cellular chemical called tumor necrosis factor (TNF). In the study, another drug that is active against TNF, Enbrel (generic name: etanercept), did not affect the risk of shingles.

Although an increased risk of bacterial infection is a well-known consequence of treatments targeting TNF, little is known about the associated risk of viral infection, Dr. Anja Strangfeld, at the German Rheumatism Research Center in Berlin, and co-authors note. However, shingles is one of the most common adverse effects reported in clinical trials of TNF blockers.

The study involved patients enrolled in the German biologics register RABBIT between May 2001 and December 2006. Included were 591 treated with Remicade, 1423 with Humira, and 1252 with Enbrel, as well as 1774 comparison subjects not treated with a TNF blocker.

Eighty-six cases of shingles occurred among 82 patients, the report indicates. Eighteen cases were serious, including 12 that required hospitalization.

Thirty-nine of the cases occurred in users of Remicade or Humira, 23 in Enbrel users, and 24 in the comparison group. In final analysis, Remicade or Humira use increased the odds of shingles by 82 percent, whereas Enbrel had no effect.

The researchers conclude by recommending “careful monitoring of patients treated with (Remicade or Humira) for early signs and symptoms of herpes zoster.”

This advice is endorsed by editorialists Dr. Richard J. Whitley and Dr. John W. Gnann, Jr., at the University of Alabama at Birmingham. “As with any therapy, time is required for all of the safety concerns related to these potent medications to become apparent.”

SOURCE: Journal of the American Medical Association, February 18, 2009.