Cetirizine and Levocetirizine interaction
Cetirizine and Levocetirizine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Cetirizine (QUZYTTIR) label · effective 2026-03-04
The use of QUZYTTIR is contraindicated in patients with a known hypersensitivity to cetirizine hydrochloride or any of its ingredients, levocetirizine, or hydroxyzine.
Known hypersensitivity to cetirizine hydrochloride or any of its ingredients, levocetirizine, or hydroxyzine ( 4 )
From the Levocetirizine (Xyzal) label · effective 2025-07-22
The use of XYZAL is contraindicated in: Patients with a known hypersensitivity to levocetirizine or any of the ingredients of XYZAL or to cetirizine ( 4.1 )
Patients with Known Hypersensitivity Patients with known hypersensitivity to levocetirizine or any of the ingredients of XYZAL, or to cetirizine.
There was a small decrease (~16%) in the clearance of cetirizine caused by a 400 mg dose of theophylline.
Ritonavir Ritonavir increased the plasma AUC of cetirizine by about 42% accompanied by an increase in half-life (53%) and a decrease in clearance (29%) of cetirizine.
Drug interaction studies have been performed with racemic cetirizine.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.