WHY DO SOME PEOPLE ITCH AFTER STOPPING ZYRTEC?

Q: I have taken Zyrtec daily for over four years to manage animal and seasonal allergies. I recently went on vacation and did not take Zyrtec during that time. (I was away from the allergy sources, after all.)

After a few days off the medicine, I developed a sudden and excruciating itching. Oddly, it felt like it came from within my body rather than on the surface. The itch started in my inner thighs and spread to my sides and back.

Luckily, I went online and searched the reactions I was having. My symptoms matched those of others who stopped Zyrtec suddenly.

Once I realized this was a withdrawal reaction, I took a Zyrtec pill. Within the hour the itching stopped. Now I am afraid to ever stop taking Zyrtec. The itch was very intense, and I don’t want to go through that again!

A: Readers of this column alerted us to this withdrawal phenomenon nearly a decade ago. At that time, cetirizine (Zyrtec) was available only by prescription. The prescribing information did not warn about a withdrawal itch reaction.

The Food and Drug Administration has now acknowledged that many people experience unbearable itching (pruritus) when they stop cetirizine suddenly (Therapeutic Advances in Drug Safety, July 5, 2019). According to the report: “Some patients described the itch as so intense that it impacted their ability to work, sleep, or perform their normal daily activities …”

The agency now requires a warning about this withdrawal reaction in the prescribing information for both cetirizine and its chemical cousin levocetirizine (Xyzal). As far as we can tell, however, this alert is not included in the overthe-counter labels.

Q: I take sildenafil (Viagra) for erectile dysfunction. It works quite well. But not long after taking it I experience pretty unpleasant heartburn. Needless to say, this interferes with the romantic mood. Do you have any recommendations?

A: All of the erectile dysfunction drugs (sildenafil, tadalafil and vardenafil, aka Viagra, Cialis and Levitra) can cause heartburn as a side effect. They work by relaxing smooth muscle that lines the blood vessels going into the penis. However, smooth muscle elsewhere in the body, such as that in the lower esophageal sphincter in the digestive tract, also relaxes in response to these drugs. That promotes acid reflux.

Ask your doctor whether taking an antacid like Tums or Rolaids along with your sildenafil might relieve heartburn. Another option might be an acidsuppressing H2 antagonist like cimetidine (Tagamet), famotidine (Pepcid) or ranitidine (Zantac).