In addition, syrup of ipecac , a solution of plant alkaloids containing the emetic compound emetine , is used orally to induce emesis. Both of these drugs act by stimulation of the stomach and a direct effect on the chemotrigger zone. A variety of phenothiazine and related analogues are useful for the treatment of nausea, and have a pronounced antiemetic effect. Prochlorperazine is not effective for preventing nausea due to motion sickness. Other compounds are more often used for this syndrome, including meclizine, dimenhydrinate and cyclizine , again due to thier effect on the chemotrigger zone.
Scopolamine patches are also effective in the relief of motion sickness.
A number of miscellaneous compounds are also effective antiemetics. The drug is practically insoluble in water, and as such is poorly absorbed from the intestine and reaches the colon intact. 5-Aminosalicylic acid is effective when administered alone, and is marketed seperately as mesalamine.