Reinforcing properties of nicocodine in the rhesus monkey.

The present study demonstrates that nicocodine is self-administered by the rhesus monkey in cross self-administration experiments. The minimum reinforcing dose is 10 times higher than that of codeine and 100 times higher than that of heroin. At reinforcing doses the rate of self-administered infusions of nicocodine is comparable with those of codeine. Further experiments are necessary to rank order nicocodine as to its positive reinforcing properties among the opiate-like compounds. On the other hand the present experiments demonstrate that nicocodine is an opium-like reinforcing compound.