Determining whether a patient has a “sweet-liking (SL) phenotype” and/or a high level of craving for alcohol may represent practical tools clinicians can use when deciding whether to prescribe naltrexone for alcohol dependence, lead author James C. Garbutt, M.D., of the Department of Psychiatry at the University of North Carolina, and colleagues wrote.
The researchers randomized 80 patients with alcohol dependence to naltrexone hydrochloride (50 mg/daily) or placebo for 12 weeks. Both groups of patients were tested to determine whether they fell into the sweet-liking or sweet-disliking (SDL) phenotype. Participants’ sensitivity and response to sweet taste was tested using five concentrations of sucrose presented in five separate blocks for a total of 25 tastings. Participants were categorized as having an SL phenotype if they rated the highest concentration of sucrose as the most pleasurable.
They found naltrexone resulted in 4.8 fewer heavy drinking days over placebo (an effect that was not statistically significant), but the SL phenotype moderated the effect of naltrexone on heavy drinking—those with the SL phenotype had 6.1 fewer heavy drinking days and 10.0 more days of abstinence. They also found that high craving for alcohol at baseline moderated the effect of naltrexone on heavy drinking, with 7.1 fewer heavy drinking days among those with high craving.
The combination of the SL phenotype and high craving was associated with the strongest response to naltrexone, with 17.1 fewer heavy drinking days and 28.8 more abstinent days compared with placebo.
“The results of the present trial support the hypothesis that the SL phenotype is a moderator of the response to naltrexone in alcohol dependence and that this effect is most apparent in the presence of a high subjective craving for alcohol,” Garbutt and colleagues wrote. “If these findings are confirmed, an assessment of the SL/SDL phenotype could be clinically useful. The phenotype shows good stability and reproducibility; is simple, safe, and inexpensive to assess; and could evolve as a simple tool to help clinicians with medication decisions.”
For related information on treating alcohol use disorder, see the Psychiatric News article “An Underutilized, Evidence-Based Treatment for Alcohol Use Disorder” by Cornel N. Stanciu, M.D.