brand logo

Am Fam Physician. 2004;69(12):2906

Clinical Question: Does cetirizine cause sedation that is unnoticed by children?

Setting: Outpatient (specialty)

Study Design: Crossover trial (randomized)

Synopsis: Sedation results in slower reaction times and impaired performance in activities that require diligent attention. Drowsiness is the subjective feeling of being tired. The two are not always connected; sedation can occur without drowsiness, and vice versa. Cetirizine has been shown not to have a sedative effect in adults, but it had not been studied in children. This study included 24 children (14 boys, 10 girls) with allergic rhinitis who were not taking medications that could affect central nervous system function.

In a research setting, the children were given a single dose of placebo, cetirizine, or chlorpheniramine in a randomized fashion. In succesive weeks, they were given the second and third options, so each child served as his or her own control subject. Sedation was measured before each dose and two hours after the dose using the P300 event-related potential neuropsychologic test. This test measures changes in brain waves and response time when the child is presented with different auditory stimuli. Drowsiness was measured using a 10-cm visual analog scale ranging from “wide awake” to “cannot stay awake.”

Compared with baseline, a significant delay in auditory response occurred when the children children received chlorpheniramine (P <.05) or cetirizine (P <.05). Chlorpheniramine has been documented to cause sedation; it was included in this study to serve as a positive control to ensure sensitivity of the outcome measures. The placebo group experienced no change. A change of at least 5 percent (a clinically relevant change) occurred in one in three of the children when they received cetirizine. However, subjective feelings of drowsiness were not significantly different in any of the groups.

Bottom Line: Some antihistamines can cause sedation without causing a subjective feeling of drowsiness. Compared with placebo, cetirizine causes changes in response time, a measure of sedation, in children. However, subjective feelings of drowsiness are not reported by those children. Although not evaluated in this study, sedation may affect learning ability. (Level of Evidence: 1c)

POEMs (patient-oriented evidence that matters) are provided by Essential Evidence Plus, a point-of-care clinical decision support system published by Wiley-Blackwell. For more information, see Copyright Wiley-Blackwell. Used with permission.

For definitions of levels of evidence used in POEMs, see

To subscribe to a free podcast of these and other POEMs that appear in AFP, search in iTunes for “POEM of the Week” or go to

This series is coordinated by Natasha J. Pyzocha, DO, contributing editor.

A collection of POEMs published in AFP is available at

Continue Reading

More in AFP

Copyright © 2004 by the American Academy of Family Physicians.

This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP.  See permissions for copyright questions and/or permission requests.