Feasibility and Preliminary Effectiveness of Varenicline for Treating Co-Occurring Cannabis and Tobacco Use.

Few studies have evaluated treatment for co-occurring cannabis and tobacco use. The objective of this pilot study was to evaluate the feasibility and preliminary effectiveness of varenicline for co-occurring cannabis and tobacco use. Participants who reported cannabis use on ≥5 days per week were recruited from an urban, outpatient opioid treatment program (OTP). Participants were randomized to either four weeks of standard OTP clinical care (SCC; medication-assisted treatment for opioid use disorder and individual behavioral counseling), followed by four weeks of SCC plus varenicline (SCC+VT), or to four weeks of SCC+VT followed by four weeks of SCC. All participants contributed feasibility and outcome data during both study phases. Of 193 persons screened, seven were enrolled. Retention at eight weeks was 100%. No adverse effects prompted varenicline discontinuation. Participants reported lower cannabis craving during the SCC+VT phase compared to baseline, and lower frequencies and quantities of cannabis use compared to both baseline and the SCC alone phase. In the SCC+VT phase, participants also reported fewer cigarettes per day. Among persons with co-occurring cannabis and tobacco use, varenicline is well-tolerated and may reduce cannabis craving, cannabis use, and tobacco use.