FDA requires warning about rare but severe itching after stopping long-term use of oral allergy medicines cetirizine or levocetirizine (Zyrtec, Xyzal, and other trade names)

Between April 25, 2017, and July 6, 2023, FDA identified 209 cases worldwide (197 domestic) of pruritus after stopping treatment with cetirizine (n=180), levocetirizine (n=27), or both (n=2), in the FDA Adverse Event Reporting System (FAERS) database.  In all 209 cases, there was a temporal relationship between discontinuing the medicine and the onset of pruritus, and the median time to onset was 2 days, with a range of 1 to 5 days.  Of these reported cases, 87 percent (n=182) were submitted by individuals using the medicines, including 6 self-identified health care professionals reporting their symptoms.  In nearly 92 percent (n=97) of the 106 pruritus cases where patients reported time length of medicine usage, the length was more than 3 months, suggesting this timeframe may be a risk predictor. The median duration of medicine use before pruritus occurrence after stopping cetirizine or levocetirizine was 33 months, with a range of 1 week to 23 years.  The number of pruritus cases increased with duration of use, suggesting that longer use may increase the risk of this reaction.  Many reports described post-discontinuation pruritus over many areas of the body that significantly affected users’ quality of life and ability to function.  Serious outcomes included disability (n=48), such as “debilitating itching to the point of being bed-ridden,” hospitalization (n=3), and thoughts of suicide or self-harm (n=2). In 92 of the 93 cases where patients reported one or more attempts at restarting then stopping the medicine, pruritus recurrence occurred.  Restarting the medicine resolved pruritus in 71/79 individuals (90 percent) and tapering off the medicine after restarting it resolved symptoms in 9/24 (38 percent) of those who tried this approach.