Varenicline raises abstinence rates in tobacco-dependent adults

Adults who are not ready to stop using tobacco had greater abstinence rates when treated with varenicline compared with placebo, according to a study published in Annals of the American Thoracic Society.

However, this treatment option resulted in a small increase in serious adverse events, according to researchers.

“This systematic review supported a strong recommendation for initiating treatment with varenicline in this population until they are ready to discontinue tobacco use,” Luciane Cruz Lopes, ScD, MSc, PhD, professor of pharmaceutical science graduate course at the University of Sorocaba in São Paulo, Brazil, and colleagues wrote.

In a systematic review and meta-analysis, Lopes and colleagues conducted a database search to identify five randomized controlled trials that included 2,616 adults who reported that they were not ready to stop using tobacco in order to establish if varenicline treatment increased their motivation to quit.

Researchers then used the Grading of Recommendations, Assessment, Development and Evaluations approach to rate the certainty of the evidence for each trial.

The study’s main outcomes included point prevalence abstinence during treatment or at 6 months or longer, adverse events, withdrawal symptoms, smoking reduction and motivation to quit.

Of the three studies (n = 2,387) with high-certainty evidence, researchers found that those treated with varenicline had greater 7-day point prevalence abstinence at 6 months or longer (RR = 2; 95% CI, 1.7-2.35; absolute risk reduction [ARR] per 1,000 patients = 173; 95% CI, 121-234) than those receiving placebo. Researchers also observed similar abstinence results during the treatment (RR = 2.49; 95% CI, 2.09-2.98; ARR per 1,000 patients = 308; 95% CI, 225-409).

However, varenicline also slightly raised the risk for serious adverse events (RR = 1.75; 95% CI, 0.98-3.13; ARR per 1,000 patients = 12; 95% CI, 0-35) compared with placebo when evaluating four studies (n = 2,415) with moderate-certainty evidence.

Through the Brief Questionnaire of Smoking Urges, researchers observed that varenicline conferred a lower withdrawal symptom score, signaling better outcomes (mean difference, –1.54 points; 95% CI, –2.15 to –0.93); however, the evidence certainty was classified as low. The Wisconsin Smoking Withdrawal scale showed comparable results with low certainty evidence as well (mean difference, –1.26; 95% CI, –1.34 to –1.18).

Researchers also found that moderate to low certainty evidence from two trials (n = 1,563) demonstrated that varenicline most likely reduced the number of cigarettes smoked by 50% or more at 4 weeks (OR = 1.95; 95% CI, 1.59-2.41), 3 months (OR = 2.03; 95% CI, 1.57-2.61) and 6 months (OR = 2.45; 95% CI, 0.53-11.33).

Additionally, starting the treatment could boost the number of quit attempts, but researchers wrote that this finding had low-certainty evidence based on three trials (n = 865; RR = 1.17; 95% CI, 0.98-1.4).

“Although high-quality evidence suggested that varenicline is beneficial for those who are not ready to discontinue tobacco use, we did not find evidence on the optimal duration of treatment, quality of life, patient adherence and the use of other substances,” Lopes and colleagues wrote. “Future research needs to include these important patient outcomes and individuals who are not ready to discontinue tobacco use and have comorbidities.

“In addition, studies on the effect of combination therapy, especially nicotine replacement therapy and varenicline, on treatment outcomes are warranted,” they added. “Finally, it is also necessary to understand patient preferences on the initiation of treatment before they are ready to discontinue tobacco use.”