Anti-emetics in development.

Despite important advances in pharmacotherapeutic options for the prevention and treatment of nausea and vomiting during the 1990s, a significant proportion of patients still suffer debilitating nausea and vomiting symptoms. The most problematic areas are chemotherapy-induced nausea and vomiting particularly delayed emesis, postoperative nausea and vomiting, opioid-induced nausea and vomiting and motion sickness. The most vigorous research into new anti-emetics has focused on the neurokinin-1 (substance P) antagonists. Clinical trials conducted to date indicate that these agents have similar efficacy to 5-HT(3) antagonists in acute chemotherapy-induced nausea and vomiting, superior efficacy to available agents in delayed emesis, possibly superior efficacy against emesis in postoperative nausea and vomiting and no evidence of efficacy versus opioid or motion-induced nausea and vomiting. Other pharmacological strategies in development include agonising CB1 (cannabinoid) receptors, "broad spectrum" receptor antagonists and 5-HT(1A) receptor agonists, although clinical trials of these types of agents are not yet available. The neurokinin-1 antagonists appear to be promising agents for some nausea and vomiting states, although further clarification of their role is required.