[A new antiemetic ramosetron hydrochloride]

Ramosetron hydrochloride as a 5-HT3 receptor antagonist-type antiemetic, which was developed in Japan. It has an indole ring which is the mother nucleus of serotonin (5-HT) and a tetrahydrobenzimidazol radical. These components are linked by a carbonyl radical. It was reported in non-clinical studies that ramosetron hydrochloride exhibited more potent and sustained antagonistic activities against 5-HT3 receptors than existing 5-HT3 receptor antagonist-type antiemetics. It was also reported that ramosetron hydrochloride inhibited vomiting by anticancer drugs in a potent and sustained manner. The phase I trial was initiated in May, 1991. Phase II and phase III trials were then conducted in a total of 357 patients at 121 institutions in Japan. The symptoms targeted in these trials were nausea and vomiting induced by anticancer drugs, such as cisplatin. Based on the results of the phase II trial, it was recommended that ramosetron hydrochloride be infected once daily at a dose of 0.3 mg. In phase III trial, a placebo-controlled double-blind study and an open trial was performed. The utility of the drug seemed to be confirmed by the results of these studies. Ramosetron hydrochloride shown an efficacy rate of 79.8% (178/223 patients) against nausea and vomiting induced by anticancer drugs, such as cisplatin when administered at a dose of 0.3 mg. The efficacy rate was 85.1% (40/47 patients) when given at a dose of 0.3 mg before the administration of anticancer drugs, such as cisplatin. The incidence of adverse effects was 2.0% (7/352 patients). Main adverse effects reported were feeling of heat, headache, and heavy feeling in the head. These adverse effects were of no clinical importance.