Pharmacological studies of furo [3,2-b]indole derivatives. II. Analgesic effect of FI-302, N-(3-piperidinopropyl)-4-methyl-6-trifluoromethyl-furo[3,2-b]ind ole-2-carboxamide, in experimental animals.

FI-302, N-(3-piperidinopropyl)-4-methyl-6-trifluoromethyl-furo[3,2-b]indol e-2-carboxamide, is a new non-steroidal anti-inflammatory compound. The analgesic effect of FI-302 was investigated in comparison with those of non-steroidal anti-inflammatory drugs (NSAIDs). In the tail pressure, hot plate and D'Amour and Smith methods, FI-302 showed a potent analgesic effect, its efficacy being about 2 to 7 times greater than those of aminopyrine, mepirizole and tiaramide. On the other hand, in these methods, aspirin, ibuprofen and phenylbutazone had little or no effect. FI-302 showed a potent inhibitory effect on the vocalization response produced by electrical stimulation. Moreover, the analgesic effect of FI-302 after intracerebroventricular injection was about 58 to 278 times more potent than those of tiaramide and ibuprofen, and about 1/6 that of morphine. However, the analgesic effect of FI-302 was not antagonized by levallorphan. From these results, it appears that FI-302 has potent analgesic effects which may be produced by both peripheral and central mechanisms, but it is a non-narcotic compound. Consequently, FI-302 should be suitably applicable for clinical purposes.