An evaluation of the ocular drying effects of 2 systemic antihistamines: loratadine and cetirizine hydrochloride.
BACKGROUND
Systemic antihistamines, such as loratadine and cetrizine hydrochloride, have proven efficacious in the control of many allergic conditions; however, patients complain about their drying effects.


OBJECTIVE
To investigate the ocular drying effects of loratadine and cetirizine hydrochloride in individuals with normal ocular health exposed to a controlled adverse environment (CAE).


METHODS
Eighteen individuals completed a randomized, double-masked study. Participants were evaluated in a CAE (a chamber that regulates humidity, temperature, airflow, and visual tasking) at baseline and after taking 10 mg of either loratadine or cetirizine hydrochloride daily for 4 days. Keratitis, conjunctival staining, and tear film break-up time (TFBUT) were examined before and after a 45-minute CAE exposure. Participant-reported ocular discomfort was recorded every 5 minutes during CAE challenge.


RESULTS
After 4 days, use of loratadine yielded a mean increase of 0.75 points (107%) in keratitis (P < .001), a mean increase of 1.35 points (133%) in conjunctival staining (P < .001), a mean decrease of 1.38 seconds (33.7%) in TFBUT (P < .001), and a mean increase of 0.32 points (24.8%) in ocular discomfort (P = .05) vs baseline. After 4 days, use of cetirizine hydrochloride yielded a mean increase of 0.57 points (60%) in keratitis (P < .001), a mean increase of 0.7 points (49.7%) in conjunctival staining (P = .005), and a mean decrease of 0.76 seconds (19.6%) in TFBUT (P = .05) vs baseline. Loratadine was shown to induce 93% greater conjunctival staining after 4 days of use and CAE exposure vs cetirizine hydrochloride (P = .04).


CONCLUSIONS
Loratadine and cetirizine hydrochloride induced signs and symptoms associated with ocular dryness, including increased corneal and conjunctival staining, decreased TFBUT, and increased ocular discomfort in healthy individuals. Loratadine induced significantly more conjunctival staining than cetirizine hydrochloride.
Ousler
George W
GW
Ophthalmic Research Associates Inc, North Andover, Massachusetts 01845, USA.
Wilcox
Katrina A
KA
Gupta
Gaurav
G
Abelson
Mark B
MB
D000328:Adult; D000368:Aged; D017332:Cetirizine / Q000009:adverse effects*; D004311:Double-Blind Method; D015352:Dry Eye Syndromes / Q000139:chemically induced*; D005260:Female; D039563:Histamine H1 Antagonists, Non-Sedating / Q000009:adverse effects*; D006801:Humans; D017336:Loratadine / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged
D039563:Histamine H1 Antagonists, Non-Sedating; D017336:Loratadine; D017332:Cetirizine