D-cycloserine and cocaine cue reactivity: preliminary findings

Abstract

Background: D-cycloserine (DCS), a partial glutamate N-methyl-D-aspartic acid (NMDA) receptor agonist, enhances extinction of conditioned fear responding in rodents and facilitates exposure-based learning in humans with anxiety disorders.

Objectives: This preliminary study investigates DCS pretreatment on response to cocaine cues in cocaine-dependent subjects.

Methods: Ten cocaine-dependent subjects were randomly assigned to receive either 50 mg DCS or matching placebo two hours before each of two 1-hour cocaine cue exposure sessions one day apart. HR and craving ratings were obtained before and during cue exposure sessions.

Results: There was a trend towards increased craving to cocaine cues in cocaine-dependent individuals after administration of DCS.

Conclusions: The administration of DCS prior to cue exposure sessions may facilitate response activation.

Scientific significance: While facilitation of extinction-based learning by DCS may have therapeutic potential for cocaine dependence, this drug may exhibit a different profile in cocaine-dependent individuals as compared to those with anxiety disorders.

Figure 1

Effect of DCS on Cocaine Cue Reactivity. DCS administered 2h prior to cocaine cue exposure sessions resulted in increased craving ratings (A), compared to placebo, during the first but not second cue exposure session. Craving ratings were not significantly different between the groups during baseline measures. Heart rate (B) was elevated after DCS, compared to placebo, although this difference did not reach statistical significance.