Acute and subchronic effects of levocetirizine and diphenhydramine on memory functioning, psychomotor performance, and mood.
BACKGROUND
Central nervous system adverse effects, such as sedation, often accompany the use of first-generation antihistamines. These effects might interfere with memory functioning and psychomotor performance. Levocetirizine was recently introduced as a new antihistamine said to be free from sedative effects.


OBJECTIVE
We sought to investigate the effects of levocetirizine (5 mg), diphenhydramine (50 mg), and placebo on memory and psychomotor performance after acute (day 1) and subchronic (day 4) daily administration in 48 healthy volunteers (24 men and 24 women).


METHODS
This study was a double-blind, placebo-controlled, randomized clinical trial. Treatments were administrated on days 1, 2, 3, and 4, 3 hours before the start of the laboratory test battery (performed on days 1 and 4), comprising a word-learning test, the Sternberg Memory Scanning Test, a tracking test (easy and hard version), and a divided attention test (tracking and memory scanning simultaneously). Statistical analyses were performed separately for days 1 and 4 by using analysis of variance.


RESULTS
On day 1, diphenhydramine significantly impaired tracking performance (easy: F(1,90) = 25.9, P <.0001; hard: F(1,90) = 20.5, P <.0001) and divided attention (tracking: F(1,90) = 23.8, P <.0001; memory scanning: F(1,90) = 22.0, P <.0001). Results on word-learning tests and Sternberg Memory Scanning Tests were not significantly impaired. On day 4, the effects of diphenhydramine did not reach significance. In contrast, on both days 1 and 4, levocetirizine did not significantly impair laboratory test performance.


CONCLUSIONS
The results show that memory, attention, and tracking performance are unaffected after acute and subchronic administration of levocetirizine (5 mg), whereas diphenhydramine (50 mg) significantly affected divided attention and tracking after acute administration.
Verster
Joris C
JC
Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands. j.c.verster@pharm.uu.nl
Volkerts
Edmund R
ER
van Oosterwijck
Armand W A A
AW
Aarab
Mounir
M
Bijtjes
Saskia I R
SI
De Weert
A Marit
AM
Eijken
Erik J E
EJ
Verbaten
Marinus N
MN
D000085:Acetates / Q000009:adverse effects*; D000328:Adult; D000339:Affect / Q000187:drug effects*; D017332:Cetirizine; D018592:Cross-Over Studies; D004155:Diphenhydramine / Q000009:adverse effects*; D004311:Double-Blind Method; D005260:Female; D006634:Histamine H1 Antagonists / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects*; D010879:Piperazines / Q000009:adverse effects*; D011597:Psychomotor Performance / Q000187:drug effects*; D012016:Reference Values; D013997:Time Factors
D000085:Acetates; D006634:Histamine H1 Antagonists; D010879:Piperazines; C472067:levocetirizine; D004155:Diphenhydramine; D017332:Cetirizine