In case of hill journey, antimotion sickness drugs are best administered at:
Twelve hours before commencing journey
One hour before commencing journey
Immediately after commencing journey
At the first feeling of motion sickness
(Ref: KDT 6/e p641) Hyoscine is administered half to one hour before journey for prevention of motion sickness. It has no role once the vomiting stas.
Other topics and Adverse effects