alpha-Fluoromethylhistidine but not diphenhydramine prevents motion-induced emesis in the cat.

PURPOSE: This study seeks to evaluate the comparative role of alpha-fluoromethylhistidine and diphenhydramine in the prevention of motion sickness.

METHOD: The role of histaminergic mechanisms in motion sickness were evaluated in a feline model. Twenty-six female cats were studied. A variety of doses of fluoromethylhistidine and diphenhydramine were administered before motion testing.

RESULTS

Fluoromethylhistidine was effective in preventing motion sickness. The efficacy was dose dependent. In contrast, diphenhydramine failed to prevent motion sickness in any of the tested doses.

CONCLUSIONS

The failure of diphenhydramine to prevent motion sickness was unexpected. This may reflect the route of administration or the animal model studied. Depletion of histamine with fluoromethylhistidine prevented motion sickness in cats. Our results suggest that this drug may provide a very long duration of protection in cats.