XYZAL: A Not-So-New Antihistamine

The antihistamine levocetirizine (XYZAL), recently approved for the treatment of hives and symptoms of hay fever, is not some sort of great breakthrough drug – it has actually been around for more than 50 years. You may well have taken it previously yourself.

To cash in on the very lucrative antihistamine market, Sanofi-Aventis, the Bridgewater, N.J.-based drugmaker, just redeveloped an old antihistamine into XYZAL so it could receive a patent for the drug. (Patents give drug inventors exclusive rights to sell the drug during a certain period of time.)

The Food and Drug Administration approved the “new” drug on May 25.

But there is no evidence that the drug treats hives or hay fever any better than any other antihistamine already out on the market. And it costs much more than other similar drugs.

In fact, the history of XYZAL provides a window into how drug companies market for profit, not the public health.

The precursor to XYZAL is hydroxyzine (ATARAX, VISTARIL), which was approved in 1956 to treat hay fever. ATARAX was promoted to relieve itching; VISTARIL, because of hydroxyzine’s sedative properties, was promoted as a tranquilizer. (Antihistamines are still sold as over-the-counter sleep aids.)

After decades on the market, ATARAX and VISTARIL both lost their patent protection, which meant that other companies were free to manufacture the same drug.

Sanofi-Aventis is not the first drug company to capitalize on the patent expiration of hydroxyzine. Other companies have taken advantage of the loss of patent protection, including Pfizer in 1995, with cetirizine (ZYRTEC). Unbeknownst to many of its users, ZYRTEC is merely a drug that results when the body processes ATARAX or VISTARIL, so it was no great advance (except for the company’s profits). 

Sanofi-Aventis’ venture is the most recent adaptation of ATARAX and VISTARIL into a so-called “new” drug. Turns out, the molecules that make up ZYRTEC have two forms: a left-handed and a right-handed form, mirror images of one another. This is analogous to the fingers on one’s left and right hands: each has the same number and types of fingers, but the hands are not identical – they are mirror images. All Sanofi-Aventis has done is separate the left hand (XYZAL) from the right – without any evidence that this improves safety or effectiveness compared to the two combined (ZYRTEC).

“Reconfiguring a drug that’s been on the market for years is a business scheme. It doesn’t advance the public health at all,” said Dr. Sidney Wolfe, director of Public Citizen’s Health Research Group.

The drug also has the same side effects as other antihistamines, including short-term memory problems, blurred vision and constipation (see box for a complete list of mental and physical side effects).

Older adults are especially sensitive to the harmful side effects of this drug and should not use drugs in this family unless absolutely necessary. Instead, patients should use chlorpheniramine (ALERMINE, CHLOR-TRIMETON) or diphenhydramine (BENADRYL, DYTAN SUSPENSION, DYTAN-D SUSPENSION, SOMINEX FORMULA). Both are available in generic form.

What You Can Do
There is no medical reason that you should be taking levocetirizine (XYZAL) rather than one of the many other prescription and non-prescription antihistamines that are available in the market.