Is Levocetirizine Less Sedating Than Cetirizine?

Is Levocetirizine Less Sedating Than Cetirizine? A Randomized, Double-blind, Placebo Controlled Trial.

The purpose of this study is to determine whether cetirizine (zyrtec), levocetirizine (xyzal), and placebo differ in the degree of sedation they produce and their relief of allergy symptoms.

Levocetirizine, the R-enantiomer of cetirizine, has been found to be less sedating relative to placebo than was cetirizine in separate trials. We plan to examine whether patients who did not tolerate cetirizine due to sedation are able to tolerate levocetirizine. This study will utilize a randomized, double-blind, placebo controlled trial comparing levocetirizine, cetirizine, and placebo in regards to sedation and allergy symptom scores. Each patient will receive levocetirizine, cetirizine, and placebo in randomized order and thus serve as their own control.

Inclusion Criteria:

• patients 18 years of age or older

• patients with perennial allergic rhinitis sensitized (positive RAST within the last 3 years or wheal greater than or equal to 3 mm within the last 3 years) to either:

  • dust mite
  • cat (if they own an indoor cat)
  • dog (if they own an indoor dog)

• will allow for sensitization to tree, grass, or weed pollen, cockroach, or mold

• history of reported sedation/somnolence when taking cetirizine

• patient must have taken cetirizine for at least 1 week prior to discontinuing it

• patients must have either tolerated levocetirizine in the past or have never tried levocetirizine.

Exclusion Criteria:

• chronic urticaria requiring ongoing antihistamine or steroid treatment
• atopic dermatitis requiring ongoing antihistamine or steroid treatment
• URI or sinus infection during the 2 weeks preceding the beginning of the study
• vasomotor (non-allergic) or irritant rhinitis
• afrin use
• elderly or over 77 years of age (could affect creatinine clearance) or chronic renal insufficiency
• patients who have not tolerated levocetirizine in the past due to sedation.
• taking other prescription or over the counter antihistamines and unwilling to stop them during the study
• the presence of a sleep disorder such as sleep apnea or narcolepsy
• the use of as needed sleeping aid medication
• the presence of other chronic medical conditions which in the opinion of the investigator would prevent the subject from being able to participate effectively