Initial evaluation of N,N-diethyl-m-toluamide and permethrin absorption in human volunteers under stress conditions.

OBJECTIVES

This was a pilot study to determine (1) whether it is feasible to effectively blind human subjects to the presence of the insect repellents N,N-diethyl-m-toluamide (DEET) and permethrin; (2) whether DEET affects the absorption of permethrin; and (3) whether combat videotape viewing and mental arithmetic are stressful.

METHODS

Ten volunteers were exposed to DEET, permethrin, and stress (1-hour combat videotape plus mental arithmetic) in a double-blind, randomized, placebo-controlled trial. Outcome measurements included hemodynamics, plasma DEET and permethrin levels, and questionnaires to assess blinding.

RESULTS

Highly sensitive serologic assays readily detected DEET but not permethrin. Staff members and subjects were effectively blinded to both. The videotape-math combination was stressful by both self-report and hemodynamic measures.

CONCLUSIONS

It is possible to blind subjects with respect to DEET and permethrin. Permethrin on clothing does not enter the bloodstream at appreciable levels. Combat videotapes and mental arithmetic can be stressful.