From the Research
Xyzal (levocetirizine) typically begins working within 1 hour after taking it, with most people experiencing symptom relief within this timeframe. For some individuals, it may take up to 2 hours to notice effects. The medication reaches maximum effectiveness in the body after about 8 hours. While you may feel relief from allergy symptoms like sneezing, itching, and runny nose quickly, it can take a few days of regular use to experience the full benefits, especially for reducing nasal congestion. Xyzal works by blocking histamine receptors, which prevents the chemical reactions that cause allergy symptoms.
Key Points to Consider
- The standard adult dose is 5 mg once daily in the evening, while children's dosing varies by age and weight 1.
- For best results, take Xyzal at the same time each day, and continue taking it regularly throughout your allergy season even if symptoms improve, as consistent use provides better symptom control.
- A meta-analysis on the early and late effects of levocetirizine on nasal obstruction under artificial and natural allergen exposure conditions is presented, demonstrating convincingly that levocetirizine shows a consistent effect on nasal obstruction as early as over the first 2 h and sustained over 6 weeks 2.
- Levocetirizine had an onset of action within 1 hour and provided significant peripheral antihistaminic activity for 28 hours after a single dose 1.
Important Considerations
- Nasal obstruction is a difficult-to-treat symptom, but levocetirizine has been shown to have decongestant properties in allergic rhinitis 3, 2.
- The pathophysiologic background of nasal obstruction and the evidence for an antihistamine, levocetirizine, in relieving nasal congestion is well-established 2.