Missing information on DEET
===========================

* Robert D. Nevin

*   © 2004 Canadian Medical Association or its licensors

In their review of the safety implications of DEET (*N*,*N*-diethyl-*m*-toluamide) for children and pregnant and lactating women, Gideon Koren and associates1 did not mention the results of animal trials involving dermal application of this repellent.

Abdel-Rahman and colleagues2 reported diffuse neuronal cell death in the brains of adult rats after 6 days of daily dermal application of DEET. They concluded that motor deficits and dysfunction of learning and memory could ensue from these changes. Similarly, Abou-Donia and collaborators3 observed impaired sensorimotor performance in rats at 30, 45 and 60 days after 60 days of daily dermal application of DEET. The impossibility of such studies in humans necessitates consideration of these data in any risk analysis.

It appears that the review by Koren and associates1 deals only with acute adverse reactions and that no long-term controlled trials measuring neurologic function in humans after dermal application of DEET have been done.

**Robert D. Nevin** General Practitioner Lockwood Clinic Toronto, Ont.

## References

1.  1. Koren G, Matsui D, Bailey B. DEET-based insect repellents: safety implications for children and pregnant and lactating women. CMAJ 2003; 169 (3):209-12.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo5OiIxNjkvMy8yMDkiO3M6NDoiYXRvbSI7czoyMToiL2NtYWovMTcwLzEvMTQuMi5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

2.  2. Abdel-Rahman A, Shetty AK, Abou-Donia MB. Subchronic dermal application of *N*,*N*-diethyl- *m*-toluamide (DEET) and permethrin to adult rats, alone or in combination, causes diffuse neuronal cell death and cytoskeletal abnormalities in the cerebral cortex and the hippocampus, and Purkinje neuron loss in the cerebellum. Exp Neurol 2001;172(1):153-71.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1006/exnr.2001.7807&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=11681848&link_type=MED&atom=%2Fcmaj%2F170%2F1%2F14.2.atom) 

3.  3. Abou-Donia MB, Goldstein LB, Dechovskaia A, Bullman S, Jones KH, Herrick EA, et al. Effects of daily dermal application of DEET and epermethrin, alone and in combination, on sensorimotor performance, blood–brain barrier, and blood–testis barrier in rats. J Toxicol Environ Health A 2001;62(7):523-41.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1080/152873901300007824&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=11289702&link_type=MED&atom=%2Fcmaj%2F170%2F1%2F14.2.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=000167736800003&link_type=ISI)