FDA warns of 'rare but severe itching' after using popular allergy medications

(NEXSTAR) – Hundreds of people who stopped using allergy medications like Zyrtec and Xyzal noticed an uncomfortable new side effect, the U.S. Food and Drug Administration said in a warning issued this month. In "rare but severe" cases, and for unknown reasons, some who quit using the drugs became very itchy and had to seek medical help.

"Reported cases were rare but sometimes serious, with patients experiencing widespread, severe itching that required medical intervention," the FDA said. The itching, known medically as pruritus, was so bad that affected people described "significant and persistent impact on quality of life and ability to function."

The FDA identified about 200 cases of this severe itching between 2017 and 2023. In most cases, the people affected had been using cetirizine or levocetirizine daily for three months or more, and only noticed the itching start after they stopped taking the allergy pills.

Cetirizine is sold over the counter under several brand names, including Zyrtec, Aller-Tec and All Day Allergy. Xyzal is a popular brand name of levocetirizine. Both ingredients are antihistamines, and may also be in prescribed medications.

Most people were able to resolve the itchiness by restarting the medication. Some were able to restart the drug then taper off more slowly.

The FDA is now revising the medications' prescribing information to include a warning about the possibility of itching.

The vast majority of people who take the drugs likely won't experience pruritus. While the FDA was able to identify more than 200 cases worldwide, tens of millions of packages of the two medications are sold over the counter every year.