Evaluation of the antihistamine effects of olopatadine and levocetirizine during a 24‐h period: A double‐blind, randomized, cross‐over, placebo‐controlled comparison in skin responses induced by histamine iontophoresis

Abstract

The antihistamine effects of olopatadine and levocetirizine, in standard-dose application described in their information (5 mg twice a day for olopatadine; 5 mg once daily for levocetirizine), were examined from 11.5 to 24 h after application. The test was designed in a double-blind, randomized, cross-over, placebo-controlled study of 12 healthy volunteers on histamine-induced flare and wheal response using an iontophoresis technique. The suppressive effect of olopatadine on the wheals induced by a 0.1-mA histamine iontophoresis lasted for 24 h after dosing. Both drugs inhibited flare induced by histamine iontophoresis almost completely until 24 h after the first administration. Suppression of the 0.2-mA-induced wheal response by levocetirizine, taken once daily, decreased with time, although 0.1-mA-induced flare was almost completely suppressed by the drug. Olopatadine completely suppressed even the wheal response induced by a 0.2-mA histamine iontophoresis. Compared with the placebo, the two drugs significantly suppressed the subjective itching assessed by visual analog scale at all intervals. There were no significant differences in subjective drowsiness and objective cognitive function between drug- and placebo-treated subjects. These results demonstrate that olopatadine seems to be more potent than levocetirizine when administrated in a standard dose. In conclusion, mild to moderate urticaria could be controlled by standard application as described in their information. On the other hand, severe urticaria could be managed by a standard application of olopatadine, but levocetirizine may need an additional dose to control severe urticaria.

Statistical reporting in randomized controlled trials from the dermatology literature: a review of 44 dermatology journals

“…After manuscript review, two were excluded for being duplicates and 27 were excluded for not being RCTs. This left 181 articles in 27 journals to be included in the review . Of these, 137 studies had parallel‐armed control groups, 42 had placebo control groups, one was a cross‐over design and one used no treatment as the control group.…”