mu-Opiate receptor agonists -- a new pharmacological approach to prevent motion sickness?

AIMS: Stress hormones might be involved in motion sickness. The influence of loperamide on kinetosis-induced nausea and stress hormone release was investigated in a placebo-controlled, cross-over study.

METHODS

Standardized rotation around the vertical axis combined with head movements was used to induce nausea 3 h after 16 mg loperamide or placebo (n = 8). Plasma antidiuretic hormone (ADH), adrenocorticotropic hormone (ACTH) and nausea ratings were investigated.

RESULTS

After loperamide nausea was significantly lower (P < 0.02). ACTH (P < 0.05) and ADH levels (P < 0.02) increased significantly in both settings, but were lower after loperamide.

CONCLUSIONS

The susceptibility to develop kinetosis-induced nausea and stress hormone release is decreased by loperamide, although the site of action remains speculative.