Depot naltrexone decreases rewarding properties of sugar in patients with opioid dependence

Abstract

Background: Opioid neurotransmission mediates hedonic value of sweet tastants; their intake may be exaggerated by the consumption of exogenous opioids (e.g., opioid dependence). Sweet Taste Test (STT) is a validated quantitative instrument assessing taste perception and hedonic features of sugar (sucrose) using a randomized and double-blind administration at five different sucrose concentrations ranging from 0.05 to 0.83 M.

Methods: The STT and cue-induced craving procedure were administered to opioid-dependent patients (n = 15) before and 1 week after the injection of a long-acting depot naltrexone (XRNT) preparation.

Results: Analyses of covariance, employing sucrose concentration and its perceived taste as covariates, showed that XRNT therapy significantly reduced the self-reported hedonic and motivational characteristics of sucrose. Greater reductions in both these characteristics were associated with more diminution in the cue-induced opioid craving.

Conclusions: Opioid antagonism in opioid-dependent subjects leads to a smaller sweet taste reward, which, in turn, may be proportional to decreased opioid craving. These pilot results support the heuristic value of the STT as a potential marker of the XRNT treatment response and call for further inquiry into potential clinical applications of the test.

Figure 1

Examples of images used in the cue-induced craving procedure. The subjects visually processed images of heroin preparation or injection (a and c) and images of housework and office work (b and d), presented in a fixed and pseudorandom order. The two stimuli classes were matched for luminosity and semantic content. All images had uniform black background and none contained human faces (see the Text).

Figure 2

Subjective self-rating for the perceived taste of the drink (−5: very bitter; +5 very sweet) along with liking the taste of the drink (−5: not at all; +5: very much) and wanting to have more of the same drink (−5: not at all; +5: very much). The data were obtained pre- and on XRNT pharmacotherapy. Results across the three sampling points were averaged and expressed as mean ± standard deviation.