The Food and Drug Administration (FDA) is alerting the public to a rare but serious side effect associated wiht discontinuing the use of cetirizine (Zyrtec) and levocetirizine (Xyzal),two widely used antihistamines. The agency plans to update the safety information on the labels of these medications, available both by prescription and over-the-counter, to include a warning about the potential for pruritus, or sudden itching, that can occur within days of stopping treatment.

The FDA emphasized that patients did not experience this itching prior to starting the medication. Patients did not experience itching before starting the medicines, the agency stated. Reported cases were rare but sometimes serious, with patients experiencing widespread, severe itching that required medical intervention.

Scope of the issue

Between April 2017 and July 2023,there were 209 reported cases of pruritus globally among individuals who stopped taking these drugs,according to the FDA. A significant majority, 94%, of these cases occurred in the United States, with 86% specifically linked to cetirizine, the active ingredient in Zyrtec.

These antihistamines are used by millions worldwide. In 2022 alone, U.S. pharmacies dispensed 26.8 million prescriptions, and consumers purchased an additional 62.7 million over-the-counter packages of these medications from retail outlets.

Despite the widespread use, the risk of pruritus after stopping these drugs remains relatively low, based on FDA data.

Key Findings on Pruritus Cases

• No reported cases involved individuals with pre-existing severe itching before starting the antihistamines.
• while some experienced pruritus after less than a month of use, 92% of cases involved those who had taken the drugs for more than three months.
• Pruritus typically developed one to five days after discontinuing treatment.
• The itching was frequently enough widespread, affecting multiple areas of the body.
• In the examined case reports, 48 individuals experienced disability, three were hospitalized, and two reported suicidal thoughts or self-harm.
• In 90% of cases,symptoms resolved upon resuming the antihistamine.

Expert Advice and Recommendations

The FDA advises individuals to consult with their healthcare providers before taking these antihistamines, even over-the-counter versions, and to discuss the potential risk of pruritus if long-term use is anticipated.

Dr. Yul Ejnes,an internal medicine specialist and clinical professor of medicine at the Alpert Medical School of brown University,suggests awareness is key. If that is the best treatment for one’s allergies, I see no reason to avoid it or to limit its use, but patients should be aware of the possibility of pruritus if they are stopping the medication after long-term use. He adds, If the itching occurs, it truly seems resuming the medication and tapering it slowly addresses the problem.

According to the FDA, a crucial factor in identifying treatment-related pruritus is a patient’s medical history.

Dr. Ejnes explains, The scenario would be that after stopping the medication, a patient feels an ‘all over’ itching without a rash or other reason to explain the itching, such as an allergic reaction or a skin condition.

Minimizing Risk and Alternative options

Dr. Purvi Parikh,a clinical assistant professor of medicine and pediatrics at New York University Langone Health,emphasizes using medications only provided that necessary. For any medicine, you should use it for the shortest amount of time needed and shouldn’t stay on anything if you don’t need it.

Dr. Parikh suggests that if long-term use is necessary,gradually tapering off the medication may help minimize the risk of pruritus. If you do end up taking drugs like Zyrtec or Xyzal for a long period of time,it may be best to taper off these medicines gradually instead of stopping cold turkey,in order to minimize the already low risk of pruritus, she advises.

For those concerned about this side effect, alternative allergy management options are available. Other options for nasal congestion or allergies are over-the-counter nasal sprays like Flonase or astepro that work well without these side effects, Dr. Parikh notes. You can also try other long-acting antihistamines that don’t have this warning, such as Allegra or Claritin.