text: The<unk> s are a class of medications which act as receptor antagonists at the<unk> -hydroxytryptamine-3 receptor <unk> -HT3 receptor), a subtype of serotonin receptor found in terminals of the vagus nerve and in certain areas of the brain.
  With the notable exception of alosetron and cilansetron, which are used in the treatment of irritable bowel syndrome, all<unk> s are antiemetics, used in the prevention and treatment of nausea and vomiting. They are particularly effective in controlling the nausea and vomiting produced by cancer chemotherapy, and are considered the gold standard for this purpose.
  The<unk> s may be identified by the suffix –setron, and are classified under code A04AA of the WHO's Anatomical Therapeutic Chemical Classification System.
option_0: 5-HT3 antagonist
option_1: Serotonin antagonist
option_2: Dopamine antagonist
option_3: Dopamine agonist
option_4: Nicotinic antagonist
option_5: NMDA receptor antagonist
option_6: Muscarinic antagonist
option_7: Alpha-adrenergic agonist