Tropisetron
Tropisetron is an indole derivative with antiemetic activity. As a selective serotonin receptor antagonist, tropisetron competitively blocks the action of serotonin at 5HT3 receptors, resulting in suppression of chemotherapy- and radiotherapy-induced nausea and vomiting.  Tropisetron appears to be well tolerated with the most frequently reported adverse effect being headache. Extrapyramidal side effects are rare upon using tropisetron.