1. Report No.

. DOT HS 809 714

2. Government Accession No.

3. Recipient's Catalog No.

4. Title and Subtitle

ANTIHISTAMINES AND DRIVING-RELATED BEHAVIOR:
A REVIEW OF THE EVIDENCE FOR IMPAIRMENT

5. Report Date

June 2004

6.  Performing Organization Code

7. Author(s)

Herbert Moskowitz, Ph.D. and Candace Jeavons Wilkinson, Ph.D.

8. Performing Organization Report No.

9. Performing Organization Name and Address

Herbert Moskowitz, Ph.D., Inc.
4138 Royal Crest Place, Encino, CA 91436

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

12. Sponsoring Agency Name and Address'

U.S. Department of Transportation
National Highway Traffic Safety Administration
400 Seventh Street, S.W
Washington, D.C.  20590

13. Type of Report and Period Covered

Final Report

Period: September 2000-February 2003

14. Sponsoring Agency Code

15. Supplementary Notes

16. Abstract

A review of the scientific literature concerning the effects of antihistamines on driving-related skills was conducted.  After reviewing all pertinent publications from 1998 and earlier, a total of 130 publications were found to meet criteria for inclusion in the data summaries.  A data base was created with study results being indexed, and summarized, by specific drug, dose, dosing schedule (i.e., single versus repeated) and H1-antagonist generation as well as by behavioral area or subjective measure.  For each H1-antagonist generation, five drugs were evaluated:   chlorpheniramine, clemastine, diphenhydramine, hydroxyzine and tripolidine for the 1^st-generation, and astemizole, cetirizine, fexofenadine, loratadine and terfenadine for the 2^nd-generation.  It was concluded that:

1.     There is some slight, but ambiguous, evidence from epidemiological studies of a connection between antihistamine use and traffic collision rates.  However, these studies were done primarily when use of only 1st-generation (but not 2^nd- generation) antihistamines was prevalent; thus, more study is needed.

2.       There is overwhelming evidence from the experimental literature that the 1^st-generation antihistamines produce objective signs of skills performance impairment as well as subjective symptoms of sedation.

3.       While 2^nd-generation antihistamines represent a major triumph for the pharmaceutical industry in reducing potential side effects, there still remains some evidence that all antihistamines, even the 2^nd- generation drugs, may cause sedation and objective skills impairment at least in some cases and for some individuals.

4.       Within both the 1^st- and 2^nd-generation antihistamine groupings, there is considerable variation in objective evidence of impairment and in subjective effects such as sedation.  Thus, there clearly are drugs that are to be preferred for use to avoid side effects such as sedation and driving-related performance impairment.

5.        Methodologically, it is apparent that among the many diverse techniques for investigating driving-related impairment, some methods and behavioral domains are more sensitive to the effects of antihistamines.  Future studies of antihistamines, therefore, must utilize the most methodologically-sound techniques so as to permit a better comparison between different drugs. 

17. Key Word

Antihistamines, Attention, Behavioral Impairment, Driving, H₁-Antagonists, Simulator, Driving-related Skills Performance

18. Distribution Statement

This document is available to the U.S. public through the National Technical Information Service

Springfield, Virginia 22161

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this page)

Unclassified

21. No. of Pages

22. Price