Mechanisms of antimotion sickness drugs.
Eight subjects, male and female, were rotated using the step method to progressively increase the speed of rotation (+2 rpm) after every 40 head movements to a maximum of 35 rpm. The end-point for motion sickness was the Graybiel Malaise III total of symptoms short of frank nausea. The drug treatments were placebo, scopolamine 0.6 mg and 1 mg, scopolamine 0.6 mg/d-amphetamine 10 mg, scopolamine 1 mg/d-amphetamine 10 mg and amphetamine 10 mg.


RESULTS
Scopolamine increased tolerated head movements over placebo level by +81, scopolamine 1 mg + 183, d-amphetamine + 118, scopolamine 0.6/d-amphetamine + 165, and scopolamine 1 mg/d-amphetamine 10 mg + 201.


CONCLUSIONS
The drugs effective in preventing motion sickness are divided into those with central acetylcholine blocking activity and those which enhance norepinephrine activity. A combination of both of these actions produces the most effective antimotion sickness medications.


CONCLUSIONS
The balance between the acetylcholine and norepinephrine activity in the CNS appears to be responsible for motion sickness.
Wood
C D
CD
Louisiana State University Medical Center, Department of Pharmacology and Therapeutics, Shreveport 71130.
Manno
J E
JE
Wood
M J
MJ
Manno
B R
BR
Redetzki
H M
HM
D000328:Adult; D003913:Dextroamphetamine / Q000627:therapeutic use*; D004111:Dimenhydrinate / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D009041:Motion Sickness / Q000517:prevention & control*; D010919:Placebos; D011398:Promethazine / Q000627:therapeutic use*; D012601:Scopolamine / Q000627:therapeutic use*
D010919:Placebos; D012601:Scopolamine; D011398:Promethazine; D004111:Dimenhydrinate; D003913:Dextroamphetamine