A new class of antiemetics: the NK-1 receptor antagonists.

Emesis is one of the most unpleasant and debilitating side effects of anticancer chemotherapy. In acute emesis (vomiting occurring 0-24 hours after chemotherapy administration), the 5-HT3 receptor antagonists and corticosteroids are highly effective, with few significant side effects, and can safely be combined. Delayed emesis (vomiting occurring >24 hours after chemotherapy administration), however, is both not well understood and less well controlled. Studies have yielded conflicting results concerning the use of 5-HT3 receptor antagonists alone in delayed emesis. The data of NK-1 receptor antagonists in the control of acute emesis, although promising, need confirmation in a properly designed study.