Discrimination of intranasal cocaine

In the development of medications for the treatment of cocaine abuse, the d rug discrimination paradigm can be used to identify medications that can at tenuate the discriminative stimulus effects of cocaine. To ascertain that p articipants are basing the discrimination on the drug's central effects, th is paradigm requires that the drug and placebo administrations do not produ ce any peripheral effects on which the discrimination can be based. This st udy examined whether intranasal cocaine (50 mg) can be discriminated from p lacebo (46 mg lactose +4 mg cocaine), how quickly this discrimination can b e made, and whether pretreatment with intranasal benzocaine can affect this discrimination. Results showed that subjects were generally able to discri minate the drug conditions correctly 15 s after administration, and this wa s unaffected by benzocaine. These results suggest that subjects base the di scrimination on peripheral drug effects (e.g. taste) that are not affected by anaesthesia of the nasal passage, and that the intranasal route of cocai ne administration is unlikely to be feasible with a drug discrimination par adigm. (C) 2000 Lippincott Williams & Wilkins.