OBJECTIVES:  The U.S. Food and Drug Administration Guidelines for the study and evaluation of gender differences in the clinical evaluation of drugs specify inclusion of women and men in clinical trials analyses on gender-specific data.  A review of several recent antimicrobial new drug applications (NDA) revealed higher rates of cutaneous hypersensitivity reactions (CHR) especially in women.  However, prevalence and gender disparity of the reactions from the recently approved drugs are not clearly understood.   METHODS: A descriptive retrospective review of all approved NDA documents from the top 3 most common drug classes in the U.S. between January 1, 2003 and December 31, 2005 was conducted.  Excluding oral contraceptives, they are anti-infectives, antidepressants, and analgesics.  Epi-info 2002 was used for statistical analyses.  RESULTS:  Of 321 NDA, 49 NDA were identified as top 3 drug classes with systemic route of administration.  Of those, 30 NDA had description of CHR as a safety outcome.  However, only 25 NDA included detailed frequency descriptions of exposure and outcomes to be used for further analysis and they are anti-infective agents (68%), analgesics (28%), and antidepressants (4%).  The drug class specific prevalence of CHR was ranged from 7.7% (analgesics) to 14.4% (antidepressants) and the rates were not significantly different between intervention and comparator groups.  Of the 25 NDA, only 3 NDA (12%) included gender specific detailed frequencies of CHR and they were all anti-infectives drugs.  The likelihood of CHR was significantly higher for women as compared to men (RR=2.37, 95% CI 1.79-3.14 in women; RR=1.15, 95% CI 0.88-1.49 in men). CONCLUSIONS: Findings from a review of all approved US NDA limited to top 3 common drug classes during 2002 and 2005 indicate that very few NDA included gender specific detailed descriptions of CHR.  Of those documented, higher rates of the reaction were observed in women.