Xyzal (levocetirizine) the same as zyrtec?

Close: Xyzal (levocetirizine) (levo-cetirizine) is the r-isomer, of zyrtec (cetirizine). Medications are usually a combination of r + s (called racemic). Typically only the r side contributes to the clinically meaningful action of the drug. So, the companies have been able to separate the active r side from the inactive s- side. This means it may be as or more effective at half the dose.