The present study used a double-blind , randomized , @ medication design , testing varenicline alone ( VAR ; @ mg twice daily ) , low dose naltrexone alone ( L-NTX ; @ mg once daily ) , varenicline plus naltrexone , and placebo for effects on cigarette craving and subjective response to alcohol and cigarettes in a sample ( n = @ ) of heavy-drinking daily smokers ( @ cigarettes/day ) .