Does Extended Pre Quit Bupropion Aid in Extinguishing Smoking Behavior?

Pharmacokinetic differences in nicotine and nicotine salts mediate reinforcement-related behavior: an animal model study

Since their introduction in the United States and Europe in 2007, electronic cigarettes (E-Cigs) have become increasingly popular among smokers. Nicotine, a key component in both tobacco and e-cigarettes, can exist in two forms: nicotine-freebase (FBN) and nicotine salts (NS). While nicotine salt is becoming more popular in e-cigarettes, the effect of nicotine salts on reinforcement-related behaviors remains poorly understood. This study aimed to compare the reinforcing effects of nicotine and nicotine salts in animal models of drug self-administration and explore potential mechanisms that may contribute to these differences. The results demonstrated that three nicotine salts (nicotine benzoate, nicotine lactate, and nicotine tartrate) resulted in greater reinforcement-related behaviors in rats compared to nicotine-freebase. Moreover, withdrawal-induced anxiety symptoms were lower in the three nicotine salt groups than in the nicotine-freebase group. The study suggested that differences in the pharmacokinetics of nicotine-freebase and nicotine salts in vivo may explain the observed behavioral differences. Overall, this study provides valuable insights into the reinforcing effects of nicotine as well as potential differences between nicotine-freebase and nicotine salts.

Associations between nicotine product use and craving among stable daily and non-daily users

Nicotine craving typically develops shortly after last use and is conceptualized as essential to the development, maintenance, and treatment of nicotine dependence. Previous research has primarily examined the relationship between craving and use among individuals trying to quit smoking, and less is known about this relationship among active users, particularly e-cigarette users. The current study evaluated the association between craving and use by assessing both constructs twice daily over 7 days in a sample of daily (n = 80) and non-daily (n = 34) users of combustible tobacco and e-cigarette products. We used negative binomial regression modeling to analyze the relationship between nicotine craving and use in two ways. First, we evaluated a lagged model in which craving at the time of assessment predicted use during the next time period. Next, we evaluated a model in which maximum craving since the last assessment predicted use during the same time period. Maximum craving was significantly and positively associated with nicotine product use (p <.05) while craving at the time of assessment was not. These associations did not differ depending on use frequency or on specific products used. Findings provide evidence that self-report ratings of craving are associated with greater nicotine and tobacco product use for both frequent and intermittent users. Furthermore, these results may be useful in developing or modifying interventions for a wide variety of nicotine users, including those who are not yet intending to make a change to their nicotine use.

Adaptive Smoking Cessation Using Precessation Varenicline or Nicotine Patch: A Randomized Clinical Trial

Importance

Adaptive pharmacotherapy, ie, starting a medication regimen and then modifying that regimen based on patient response, is common in many medical domains but is not common in smoking cessation. Recently, studies have found that adaptive treatment using precessation nicotine patches is efficacious for smoking cessation; however, adaptive treatment using precessation varenicline and adaptive treatment in clinical practice settings have not been fully assessed.

Objective

To determine whether adaptive pharmacotherapy leads to higher smoking abstinence rates than standard pharmacotherapy in a clinical practice setting.

Design, Setting, and Participants

This double-blinded stratified placebo-controlled randomized clinical trial compared adaptive treatment with standard treatment for smoking cessation. The study was conducted at a university health system in Durham, North Carolina, from February 2018 to May 2020 and was stopped early due to COVID-19. Data were analyzed as intent-to-treat from May 24, 2021, to February 27, 2022.

Interventions

Participants were allowed to choose varenicline or nicotine patches and were then randomized to adaptive or nonadaptive (standard) treatment. Participants started on their chosen medication (adaptive) or placebo (standard) 4 weeks before their target quit day. Two weeks later, participants were assessed for treatment response. Adaptive participants who did not decrease daily cigarettes smoked by at least 50% (nonresponders) received bupropion in addition to their chosen medication. Participants in the adaptative treatment group who did decrease daily cigarettes smoked by at least 50% (responders) and participants in the standard treatment group received additional placebo bupropion. Participants in the standard treatment group received varenicline starting 1 week before the target quit date or nicotine patches starting on the target quit day. All participants received brief behavioral support.

Main Outcome and Measures

The main outcome was biochemically verified 30-day continuous smoking abstinence 12 weeks after their target quit smoking day. Other measures included demographic characteristics, smoking history, and repeated smoking assessments.

Results

Of the planned 300 participants, a total of 188 participants (mean [SD] age, 49.1 [12.5] years; 102 [54%] female) were enrolled before the trial was stopped because of the COVID-19 pandemic. A total of 127 participants chose to use varenicline, including 64 randomized to adaptive treatment and 63 randomized to standard treatment, and 61 participants chose to use nicotine patches, including 31 randomized to adaptive treatment and 30 randomized to standard treatment. At baseline, participants smoked a mean (SD) of 15.4 (7.3) cigarettes per day. At 12 weeks after the target quit day, biochemically verified 30-day continuous smoking abstinence was observed in 23 of 95 participants (24%) in the adaptive treatment group and 8 of 93 participants (9%) in the standard treatment (odds ratio [OR], 3.38; 95% CI, 1.43-7.99; P = .004); among participants who used varenicline, 30-day continuous abstinence was 18 participants (28%) in the adaptive treatment group, and 5 participants (8%) in the standard treatment group (OR, 4.54; 95% CI, 1.57-13.15); among participants who used nicotine patches, 30-day continuous abstinence was 5 participants (16%) in the adaptive treatment group and 3 participants (10%) in the standard treatment group (OR, 1.73; 95% CI, 0.38-7.99). Sleep problems were more common for participants in the varenicline adaptive treatment group than in the varenicline standard treatment group (rate ratio, 1.74; 95% CI, 1.18-2.58; P = .03).

Conclusions and Relevance

This randomized clinical trial found that adaptive pharmacotherapy was efficacious for smoking cessation treatment in a practice setting.

Trial Registration

ClinicalTrials.gov Identifier: NCT02501265.

Antidepressants for smoking cessation

BACKGROUND

The pharmacological profiles and mechanisms of antidepressants are varied. However, there are common reasons why they might help people to stop smoking tobacco: nicotine withdrawal can produce short-term low mood that antidepressants may relieve; and some antidepressants may have a specific effect on neural pathways or receptors that underlie nicotine addiction.

OBJECTIVES

To assess the evidence for the efficacy, harms, and tolerability of medications with antidepressant properties in assisting long-term tobacco smoking cessation in people who smoke cigarettes.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialised Register, most recently on 29 April 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in people who smoked, comparing antidepressant medications with placebo or no pharmacological treatment, an alternative pharmacotherapy, or the same medication used differently. We excluded trials with fewer than six months of follow-up from efficacy analyses. We included trials with any follow-up length for our analyses of harms.

DATA COLLECTION AND ANALYSIS

We extracted data and assessed risk of bias using standard Cochrane methods. Our primary outcome measure was smoking cessation after at least six months' follow-up. We used the most rigorous definition of abstinence available in each trial, and biochemically validated rates if available. Our secondary outcomes were harms and tolerance outcomes, including adverse events (AEs), serious adverse events (SAEs), psychiatric AEs, seizures, overdoses, suicide attempts, death by suicide, all-cause mortality, and trial dropouts due to treatment. We carried out meta-analyses where appropriate.

MAIN RESULTS

We included a total of 124 studies (48,832 participants) in this review, with 10 new studies added to this update version. Most studies recruited adults from the community or from smoking cessation clinics; four studies focused on adolescents (with participants between 12 and 21 years old). We judged 34 studies to be at high risk of bias; however, restricting analyses only to studies at low or unclear risk of bias did not change clinical interpretation of the results.  There was high-certainty evidence that bupropion increased smoking cessation rates when compared to placebo or no pharmacological treatment (RR 1.60, 95% CI 1.49 to 1.72; I2 = 16%; 50 studies, 18,577 participants). There was moderate-certainty evidence that a combination of bupropion and varenicline may have resulted in superior quit rates to varenicline alone (RR 1.21, 95% CI 0.95 to 1.55; I2 = 15%; 3 studies, 1057 participants). However, there was insufficient evidence to establish whether a combination of bupropion and nicotine replacement therapy (NRT) resulted in superior quit rates to NRT alone (RR 1.17, 95% CI 0.95 to 1.44; I2 = 43%; 15 studies, 4117 participants; low-certainty evidence). There was moderate-certainty evidence that participants taking bupropion were more likely to report SAEs than those taking placebo or no pharmacological treatment. However, results were imprecise and the CI also encompassed no difference (RR 1.16, 95% CI 0.90 to 1.48; I2 = 0%; 23 studies, 10,958 participants). Results were also imprecise when comparing SAEs between people randomised to a combination of bupropion and NRT versus NRT alone (RR 1.52, 95% CI 0.26 to 8.89; I2 = 0%; 4 studies, 657 participants) and randomised to bupropion plus varenicline versus varenicline alone (RR 1.23, 95% CI 0.63 to 2.42; I2 = 0%; 5 studies, 1268 participants). In both cases, we judged evidence to be of low certainty. There was high-certainty evidence that bupropion resulted in more trial dropouts due to AEs than placebo or no pharmacological treatment (RR 1.44, 95% CI 1.27 to 1.65; I2 = 2%; 25 studies, 12,346 participants). However, there was insufficient evidence that bupropion combined with NRT versus NRT alone (RR 1.67, 95% CI 0.95 to 2.92; I2 = 0%; 3 studies, 737 participants) or bupropion combined with varenicline versus varenicline alone (RR 0.80, 95% CI 0.45 to 1.45; I2 = 0%; 4 studies, 1230 participants) had an impact on the number of dropouts due to treatment. In both cases, imprecision was substantial (we judged the evidence to be of low certainty for both comparisons). Bupropion resulted in inferior smoking cessation rates to varenicline (RR 0.73, 95% CI 0.67 to 0.80; I2 = 0%; 9 studies, 7564 participants), and to combination NRT (RR 0.74, 95% CI 0.55 to 0.98; I2 = 0%; 2 studies; 720 participants). However, there was no clear evidence of a difference in efficacy between bupropion and single-form NRT (RR 1.03, 95% CI 0.93 to 1.13; I2 = 0%; 10 studies, 7613 participants). We also found evidence that nortriptyline aided smoking cessation when compared with placebo (RR 2.03, 95% CI 1.48 to 2.78; I2 = 16%; 6 studies, 975 participants), and some evidence that bupropion resulted in superior quit rates to nortriptyline (RR 1.30, 95% CI 0.93 to 1.82; I2 = 0%; 3 studies, 417 participants), although this result was subject to imprecision. Findings were sparse and inconsistent as to whether antidepressants, primarily bupropion and nortriptyline, had a particular benefit for people with current or previous depression.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that bupropion can aid long-term smoking cessation. However, bupropion may increase SAEs (moderate-certainty evidence when compared to placebo/no pharmacological treatment). There is high-certainty evidence that people taking bupropion are more likely to discontinue treatment compared with people receiving placebo or no pharmacological treatment. Nortriptyline also appears to have a beneficial effect on smoking quit rates relative to placebo, although bupropion may be more effective. Evidence also suggests that bupropion may be as successful as single-form NRT in helping people to quit smoking, but less effective than combination NRT and varenicline. In most cases, a paucity of data made it difficult to draw conclusions regarding harms and tolerability. Further studies investigating the efficacy of bupropion versus placebo are unlikely to change our interpretation of the effect, providing no clear justification for pursuing bupropion for smoking cessation over other licensed smoking cessation treatments; namely, NRT and varenicline. However, it is important that future studies of antidepressants for smoking cessation measure and report on harms and tolerability.

Effect of Extending the Duration of Prequit Treatment With Varenicline on Smoking Abstinence: A Randomized Clinical Trial

IMPORTANCE

Even with varenicline, the leading monotherapy for tobacco dependence, smoking abstinence rates remain low. Preliminary evidence suggests that extending the duration of varenicline treatment before quitting may increase abstinence.

OBJECTIVE

To test the hypotheses that, compared with standard run-in varenicline treatment (1 week before quitting), extended run-in varenicline treatment (4 weeks before quitting) reduces smoking exposure before the target quit date (TQD) and enhances abstinence, particularly among women.

DESIGN, SETTING, AND PARTICIPANTS

This double-blind, randomized, placebo-controlled clinical trial enrolled participants from October 2, 2017, to December 9, 2020, at a single-site research clinic in Buffalo, New York. Of 1385 people screened, 320 adults reporting smoking 5 or more cigarettes per day (CPD) were randomized and followed up for 28 weeks. Data were analyzed from August 2021 to June 2022.

INTERVENTIONS

In the pre-TQD period (weeks 1-4), the extended run-in group received 4 weeks of varenicline; the standard run-in group received 3 weeks of placebo followed by 1 week of varenicline. Both groups received open-label varenicline during weeks 5 to 15 and brief quit counseling at 6 clinic visits.

MAIN OUTCOMES AND MEASURES

The primary outcome consisted of cotinine-verified (at end of treatment [EOT]) self-reported continuous abstinence from smoking (in CPD) during the last 4 weeks of treatment. Secondary outcomes included bioverified self-report of continuous abstinence at the 6-month follow-up and percentage of reduction in self-reported smoking rate during the prequit period (week 1 vs week 4).

RESULTS

A total of 320 participants were randomized, including 179 women (55.9%) and 141 men (44.1%), with a mean (SD) age of 53.7 (10.1) years. Continuous abstinence during the final 4 weeks of treatment (weeks 12-15; EOT) was not greater in the extended run-in group (64 of 163 [39.3%]) compared with the standard run-in group (57 of 157 [36.3%]; odds ratio [OR], 1.13 [95% CI, 0.72-1.78]), nor was the hypothesized group × sex interaction significant (OR, 0.52 [95% CI, 0.21-1.28]). Similar nonsignificant results were obtained for continuous abstinence at the 6-month follow-up. The mean (SE) decrease in self-reported smoking rate during the prequit period was greater in the extended run-in group (-38.8% [2.8%]) compared with the standard run-in group (-17.5% [2.7%]).

CONCLUSIONS AND RELEVANCE

Among adult daily smokers, extending the duration of prequit varenicline treatment beyond the standard 1-week run-in period reduced prequit smoking exposure but, more importantly, did not significantly improve continuous abstinence rates.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03262662.

Antidepressants for smoking cessation

BACKGROUND

Whilst the pharmacological profiles and mechanisms of antidepressants are varied, there are common reasons why they might help people to stop smoking tobacco. Firstly, nicotine withdrawal may produce depressive symptoms and antidepressants may relieve these. Additionally, some antidepressants may have a specific effect on neural pathways or receptors that underlie nicotine addiction.

OBJECTIVES

To assess the evidence for the efficacy, safety and tolerability of medications with antidepressant properties in assisting long-term tobacco smoking cessation in people who smoke cigarettes.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Specialized Register, which includes reports of trials indexed in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO, clinicaltrials.gov, the ICTRP, and other reviews and meeting abstracts, in May 2019.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that recruited smokers, and compared antidepressant medications with placebo or no treatment, an alternative pharmacotherapy, or the same medication used in a different way. We excluded trials with less than six months follow-up from efficacy analyses. We included trials with any follow-up length in safety analyses.

DATA COLLECTION AND ANALYSIS

We extracted data and assessed risk of bias using standard Cochrane methods. We also used GRADE to assess the certainty of the evidence. The primary outcome measure was smoking cessation after at least six months follow-up, expressed as a risk ratio (RR) and 95% confidence intervals (CIs). We used the most rigorous definition of abstinence available in each trial, and biochemically validated rates if available. Where appropriate, we performed meta-analysis using a fixed-effect model. Similarly, we presented incidence of safety and tolerance outcomes, including adverse events (AEs), serious adverse events (SAEs), psychiatric AEs, seizures, overdoses, suicide attempts, death by suicide, all-cause mortality, and trial dropout due to drug, as RRs (95% CIs).

MAIN RESULTS

We included 115 studies (33 new to this update) in this review; most recruited adult participants from the community or from smoking cessation clinics. We judged 28 of the studies to be at high risk of bias; however, restricting analyses only to studies at low or unclear risk did not change clinical interpretation of the results. There was high-certainty evidence that bupropion increased long-term smoking cessation rates (RR 1.64, 95% CI 1.52 to 1.77; I² = 15%; 45 studies, 17,866 participants). There was insufficient evidence to establish whether participants taking bupropion were more likely to report SAEs compared to those taking placebo. Results were imprecise and CIs encompassed no difference (RR 1.16, 95% CI 0.90 to 1.48; I² = 0%; 21 studies, 10,625 participants; moderate-certainty evidence, downgraded one level due to imprecision). We found high-certainty evidence that use of bupropion resulted in more trial dropouts due to adverse events of the drug than placebo (RR 1.37, 95% CI 1.21 to 1.56; I² = 19%; 25 studies, 12,340 participants). Participants randomized to bupropion were also more likely to report psychiatric AEs compared with those randomized to placebo (RR 1.25, 95% CI 1.15 to 1.37; I² = 15%; 6 studies, 4439 participants). We also looked at the safety and efficacy of bupropion when combined with other non-antidepressant smoking cessation therapies. There was insufficient evidence to establish whether combination bupropion and nicotine replacement therapy (NRT) resulted in superior quit rates to NRT alone (RR 1.19, 95% CI 0.94 to 1.51; I² = 52%; 12 studies, 3487 participants), or whether combination bupropion and varenicline resulted in superior quit rates to varenicline alone (RR 1.21, 95% CI 0.95 to 1.55; I² = 15%; 3 studies, 1057 participants). We judged the certainty of evidence to be low and moderate, respectively; in both cases due to imprecision, and also due to inconsistency in the former. Safety data were sparse for these comparisons, making it difficult to draw clear conclusions. A meta-analysis of six studies provided evidence that bupropion resulted in inferior smoking cessation rates to varenicline (RR 0.71, 95% CI 0.64 to 0.79; I² = 0%; 6 studies, 6286 participants), whilst there was no evidence of a difference in efficacy between bupropion and NRT (RR 0.99, 95% CI 0.91 to 1.09; I² = 18%; 10 studies, 8230 participants). We also found some evidence that nortriptyline aided smoking cessation when compared with placebo (RR 2.03, 95% CI 1.48 to 2.78; I² = 16%; 6 studies, 975 participants), whilst there was insufficient evidence to determine whether bupropion or nortriptyline were more effective when compared with one another (RR 1.30 (favouring bupropion), 95% CI 0.93 to 1.82; I² = 0%; 3 studies, 417 participants). There was no evidence that any of the other antidepressants tested (including St John's Wort, selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs)) had a beneficial effect on smoking cessation. Findings were sparse and inconsistent as to whether antidepressants, primarily bupropion and nortriptyline, had a particular benefit for people with current or previous depression.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that bupropion can aid long-term smoking cessation. However, bupropion also increases the number of adverse events, including psychiatric AEs, and there is high-certainty evidence that people taking bupropion are more likely to discontinue treatment compared with placebo. However, there is no clear evidence to suggest whether people taking bupropion experience more or fewer SAEs than those taking placebo (moderate certainty). Nortriptyline also appears to have a beneficial effect on smoking quit rates relative to placebo. Evidence suggests that bupropion may be as successful as NRT and nortriptyline in helping people to quit smoking, but that it is less effective than varenicline. There is insufficient evidence to determine whether the other antidepressants tested, such as SSRIs, aid smoking cessation, and when looking at safety and tolerance outcomes, in most cases, paucity of data made it difficult to draw conclusions. Due to the high-certainty evidence, further studies investigating the efficacy of bupropion versus placebo are unlikely to change our interpretation of the effect, providing no clear justification for pursuing bupropion for smoking cessation over front-line smoking cessation aids already available. However, it is important that where studies of antidepressants for smoking cessation are carried out they measure and report safety and tolerability clearly.

Reduction in Cigarettes per Day Prospectively Predicts Making a Quit Attempt: A Fine-Grained Secondary Analysis of a Natural History Study

INTRODUCTION

Reducing cigarettes per day (CPD) aided by medication increases quit attempts (QA) among smokers not trying to quit. If this is due to reducing CPD per se, then a greater reduction should predict making a QA.

AIMS AND METHODS

In this secondary analysis, 132 smokers completed nightly calls to report CPD, intention to quit tomorrow, and QAs over 12 weeks. We provided no treatment. We identified episodes of reduction and tested whether (1) percent reduction in CPD, (2) absolute reduction in CPD, (3) duration of reduction, or (4) CPD on the final day predicted a QA immediately after a reduction episode. We tested this separately among reduction episodes that began with and without an intention to quit.

RESULTS

Among the 1179 episodes that began without intention to quit, all four measures of reduction predicted making a QA. Greater percent reduction, longer duration, and fewer CPD on the final day were retained in a multivariate model (all p < .05). Among the 85 episodes that began with intention to quit, greater percent reduction and greater absolute reduction predicted making a QA. Only mean percent reduction was retained in a multivariate model (p < .001).

CONCLUSIONS

Our results replicate and extend earlier studies by using fine-grained analyses and examining immediately proximal QAs in a sample of self-quitters. Findings suggest that reducing CPD per se increases the probability of a QA among smokers without intention to quit in a dose-related manner. Whether this is the case among smokers who intend to quit remains unclear.

IMPLICATIONS

Reducing CPD appears to be an effective strategy to increase the probability of making a QA for the majority of smokers who do not intend to quit in the near future. However, our findings are mixed regarding the effectiveness of reducing among smokers who intend to quit. Clinical interventions and policies that promote reducing CPD are likely to be an effective way to increase QAs. Reduction may be especially helpful for smokers who have not responded to traditional advice to stop abruptly.

A Randomized Controlled Trial of an Optimized Smoking Treatment Delivered in Primary Care

Background

The effectiveness of smoking cessation treatment is limited in real-world use, perhaps because we have not selected the components of such treatments optimally nor have treatments typically been developed for and evaluated in real-world clinical settings.

Purpose

To validate an optimized smoking cessation treatment package that comprises intervention components identified as effective in factorial screening experiments conducted as per the Multiphase Optimization Strategy (MOST).

Methods

Adult smokers motivated to quit were recruited from primary care clinics (N = 623). Participants were randomized to receive either recommended usual care (R-UC; 10 min of in-person counseling, 8 weeks of nicotine patch, and referral to quitline services) or abstinence-optimized treatment (A-OT; 3 weeks of prequit mini-lozenges, 26 weeks of nicotine patch + mini-lozenges, three in-person and eight phone counseling sessions, and 7-11 automated calls to prompt medication use). The key outcomes were self-reported and biochemically confirmed (carbon monoxide, CO <6 ppm) 7-day point-prevalence abstinence.

Results

A-OT participants had significantly higher self-reported abstinence rates than R-UC participants at 4, 8, 16, and 26 weeks (ORs: 1.91-3.05; p <. 001). The biochemically confirmed 26-week abstinence rates were lower than the self-reported 26-week rates, but revealed a similar treatment effect size (OR = 2.94, p < .001). There was no moderation of treatment effects on 26-week abstinence by demographic, psychiatric, or nicotine dependence variables. A-OT had an incremental cost-effectiveness ratio for 26-week CO-confirmed abstinence of $7,800.

Conclusions

A smoking cessation treatment that is optimized via MOST development meaningfully enhances cessation rates beyond R-UC smoking treatment in smokers seen in primary care.

Clinical Trial Registration

NCT02301403.

Smoking reduction interventions for smoking cessation

BACKGROUND

The standard way most people are advised to stop smoking is by quitting abruptly on a designated quit day. However, many people who smoke have tried to quit many times and may like to try an alternative method. Reducing smoking behaviour before quitting could be an alternative approach to cessation. However, before this method can be recommended it is important to ensure that abrupt quitting is not more effective than reducing to quit, and to determine whether there are ways to optimise reduction methods to increase the chances of cessation.

OBJECTIVES

To assess the effect of reduction-to-quit interventions on long-term smoking cessation.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialised Register, MEDLINE, Embase and PsycINFO for studies, using the terms: cold turkey, schedul*, cut* down, cut-down, gradual*, abrupt*, fading, reduc*, taper*, controlled smoking and smoking reduction. We also searched trial registries to identify unpublished studies. Date of the most recent search: 29 October 2018.

SELECTION CRITERIA

Randomised controlled trials in which people who smoked were advised to reduce their smoking consumption before quitting smoking altogether in at least one trial arm. This advice could be delivered using self-help materials or behavioural support, and provided alongside smoking cessation pharmacotherapies or not. We excluded trials that did not assess cessation as an outcome, with follow-up of less than six months, where participants spontaneously reduced without being advised to do so, where the goal of reduction was not to quit altogether, or where participants were advised to switch to cigarettes with lower nicotine levels without reducing the amount of cigarettes smoked or the length of time spent smoking. We also excluded trials carried out in pregnant women.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods. Smoking cessation was measured after at least six months, using the most rigorous definition available, on an intention-to-treat basis. We calculated risk ratios (RRs) and 95% confidence intervals (CIs) for smoking cessation for each study, where possible. We grouped eligible studies according to the type of comparison (no smoking cessation treatment, abrupt quitting interventions, and other reduction-to-quit interventions) and carried out meta-analyses where appropriate, using a Mantel-Haenszel random-effects model. We also extracted data on quit attempts, pre-quit smoking reduction, adverse events (AEs), serious adverse events (SAEs) and nicotine withdrawal symptoms, and meta-analysed these where sufficient data were available.

MAIN RESULTS

We identified 51 trials with 22,509 participants. Most recruited adults from the community using media or local advertising. People enrolled in the studies typically smoked an average of 23 cigarettes a day. We judged 18 of the studies to be at high risk of bias, but restricting the analysis only to the five studies at low or to the 28 studies at unclear risk of bias did not significantly alter results.We identified very low-certainty evidence, limited by risk of bias, inconsistency and imprecision, comparing the effect of reduction-to-quit interventions with no treatment on cessation rates (RR 1.74, 95% CI 0.90 to 3.38; I2 = 45%; 6 studies, 1599 participants). However, when comparing reduction-to-quit interventions with abrupt quitting (standard care) we found evidence that neither approach resulted in superior quit rates (RR 1. 01, 95% CI 0.87 to 1.17; I2 = 29%; 22 studies, 9219 participants). We judged this estimate to be of moderate certainty, due to imprecision. Subgroup analysis provided some evidence (P = 0.01, I2 = 77%) that reduction-to-quit interventions may result in more favourable quit rates than abrupt quitting if varenicline is used as a reduction aid. Our analysis comparing reduction using pharmacotherapy with reduction alone found low-certainty evidence, limited by inconsistency and imprecision, that reduction aided by pharmacotherapy resulted in higher quit rates (RR 1. 68, 95% CI 1.09 to 2.58; I2 = 78%; 11 studies, 8636 participants). However, a significant subgroup analysis (P < 0.001, I2 = 80% for subgroup differences) suggests that this may only be true when fast-acting NRT or varenicline are used (both moderate-certainty evidence) and not when nicotine patch, combination NRT or bupropion are used as an aid (all low- or very low-quality evidence). More evidence is likely to change the interpretation of the latter effects.Although there was some evidence from within-study comparisons that behavioural support for reduction to quit resulted in higher quit rates than self-help resources alone, the relative efficacy of various other characteristics of reduction-to-quit interventions investigated through within- and between-study comparisons did not provide any evidence that they enhanced the success of reduction-to-quit interventions. Pre-quit AEs, SAEs and nicotine withdrawal symptoms were measured variably and infrequently across studies. There was some evidence that AEs occurred more frequently in studies that compared reduction using pharmacotherapy versus no pharmacotherapy; however, the AEs reported were mild and usual symptoms associated with NRT use. There was no clear evidence that the number of people reporting SAEs, or changes in withdrawal symptoms, differed between trial arms.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that neither reduction-to-quit nor abrupt quitting interventions result in superior long-term quit rates when compared with one another. Evidence comparing the efficacy of reduction-to-quit interventions with no treatment was inconclusive and of low certainty. There is also low-certainty evidence to suggest that reduction-to-quit interventions may be more effective when pharmacotherapy is used as an aid, particularly fast-acting NRT or varenicline (moderate-certainty evidence). Evidence for any adverse effects of reduction-to-quit interventions was sparse, but available data suggested no excess of pre-quit SAEs or withdrawal symptoms. We downgraded the evidence across comparisons due to risk of bias, inconsistency and imprecision. Future research should aim to match any additional components of multicomponent reduction-to-quit interventions across study arms, so that the effect of reduction can be isolated. In particular, well-conducted, adequately-powered studies should focus on investigating the most effective features of reduction-to-quit interventions to maximise cessation rates.

Facilitated Extinction Training to Improve Pharmacotherapy for Smoking Cessation: A Pilot Feasibility Trial

Introduction

Varenicline reduces smoking satisfaction during the pre-cessation run-in period, which may contribute to extinction of cravings and smoking behavior. Research indicates that efficacy is enhanced when the run-in period is increased from 1 to 4 weeks, providing a longer extinction opportunity. We hypothesized that efficacy could be further enhanced by harnessing basic and applied research on extinction. We developed a pre-cessation extinction-facilitating intervention and tested its feasibility in a pilot trial.

Methods

The facilitated extinction (FE) intervention comprised brief counseling and workbook-recommending strategies to maximize extinction processes during the run-in, including instructions to smoke at a normal rate across contexts and cues, and use of an extinction cue to enhance generalization. Participants were randomly assigned to one of three varenicline interventions: standard (1-week run-in), extended (4-week run-in), and extended + FE. Interventions were delivered prior to the target quit date (TQD). Assessments were conducted in weeks 1 and 4 pre-TQD and 1 and 3 months post-TQD, with focus on feasibility indices.

Results

Recruitment and retention goals were met (N = 58). Treatment satisfaction was high across groups. The majority of FE participants adhered to instructions and maintained their usual smoking rate during the run-in period. Greater decreases in craving and smoking satisfaction were observed among participants in both extended groups versus the standard group (p < .005).

Conclusions

Feasibility was demonstrated. Participants adhered to the FE intervention, thereby optimizing the number and variety of extinction trials. Findings support testing the novel FE smoking cessation intervention in a fully powered trial.

Implications

This study expands the research on the clinical benefits of extending the pre-cessation run-in period of varenicline. It introduces the hypothesis that further benefit might be achieved by translating basic behavioral research, as well as cue-exposure research and therapy for other disorders, to improve the extinction and generalization processes thought to underlie much of varenicline's effect. A FE intervention was developed and found acceptable to smokers and feasible to implement in a research setting. The study sets the stage for a subsequent randomized controlled trial.

Progressive nicotine patch dosing prior to quitting smoking: feasibility, safety and effects during the pre-quit and post-quit periods

BACKGROUND AND AIMS

Nicotine replacement therapy (NRT) may be more effective in aiding smoking cessation if higher doses of nicotine from it can be tolerated. We examined the responses to, and 4-week abstinence rates observed, when titrating the dose of transdermal nicotine patch up to 84 mg/day over 4 weeks prior to a target quit date and titrating down again over 4 weeks afterwards.

DESIGN

Clinical cohort study.

SETTING

Tobacco dependence clinic, Mar del Plata, Argentina.

PARTICIPANTS

Fifty smokers seeking help with stopping smoking.

INTERVENTION

Participants started on one 21-mg/24-hour patch 4 weeks prior to their target quit day (TQD). The dose was increased weekly by adding a 21-mg patch unless participants reported adverse effects and/or did not wish to increase the dose. The dose was reduced by 21 mg/day each week from 1 week post-TQD, until it reverted to the standard dose (21 mg/day) at 4 weeks post-TQD. Participants received weekly behavioural support and could also use oral NRT from the TQD. Participants were advised to smoke ad libitum during the pre-quit period.

MEASUREMENTS

Proportion of participants progressing through each stage of dosing, adherence, adverse effects, changes in cigarette consumption, smoke intake and enjoyment of smoking during the pre-quit period; withdrawal symptoms; carbon monoxide-validated abstinence during 4 weeks post-TQD.

FINDINGS

Of the 50 participants, 72.0% (n = 36) progressed to the 84-mg nicotine dose and 94.0% (n = 47) completed the trial. Adverse effects consisted primarily of nausea and were mild and well tolerated. Cigarette consumption, smoke intake and enjoyment of smoking declined significantly during the pre-quit period. Forty-one (82%) participants achieved 4 weeks validated abstinence. Abstainers experienced no detectable cigarette withdrawal symptoms.

CONCLUSIONS

Most smokers seeking help with stopping appear to be able to tolerate doses of transdermal nicotine patch up to 84 mg/day during a 4-week pre-quit up-titration period with minimal side effects.

Mediators of the effect of nicotine pre-treatment on quitting smoking

BACKGROUND AND AIMS

Using smoking cessation medications for several weeks prior to quitting smoking facilitates quitting success, but how it does so is not clear. Candidate theories are that pre-cessation medication enhances self-efficacy, facilitates medication adherence post-quit, induces aversion to smoking, reduces reward from smoking or reduces the drive to smoke. We investigated these pathways using data from a large trial of nicotine pre-loading, using mediation analysis.

DESIGN

Randomized controlled trial of nicotine pre-loading. Potential mediators were assessed at baseline and 1 week into the pre-loading (3 weeks prior to quitting). In addition to this, urges to smoke in abstainers were assessed 1 week after the target quit date.

SETTING

England.

PARTICIPANTS

A total of 1792 smokers who wanted to quit attending specialist smoking cessation services in England were enrolled between 13 August 2012 and 10 March 2015.

INTERVENTION AND COMPARATOR

Participants were randomized to either standard smoking cessation medications accompanied by behavioural support or the same treatment supplemented by nicotine 'pre-loading', i.e. 4 weeks of 21 mg nicotine patch use prior to quitting.

MEASUREMENTS

The primary outcome, selected for its proximity in time to potential mediators, was biochemically validated abstinence from smoking at 4 weeks post-target quit date. Potential mediators included the Modified Cigarette Evaluation Questionnaire, with subscales assessing satisfaction, reward, craving and aversion; ratings of strength and frequency of urges to smoke; the Mood and Physical Symptoms Scale assessing cigarette withdrawal symptoms; two items from the Nicotine Dependence Syndrome Scale assessing smoking stereotypy; self-reported reduction in cigarettes per day and in carbon monoxide (CO) reading; post-target quit day (TQD) medication adherence; self-efficacy; nausea.

FINDINGS

Pre-loading reduced urges to smoke at 3 weeks pre-quit (P < 0.001) and exhaled CO concentrations (P < 0.001), and also urges to smoke post-quit in abstainers (P = 0.001). At 3 weeks pre-quit, it also reduced cigarette consumption, enjoyment of and satisfaction from smoking and smoking reward and increased nausea, aversion (all P < 0.001) and smoking stereotypy (P = 0.003). Only the first three variables, however (reduced smoke intake and reduced urges to smoke pre- and post-quit), mediated abstinence from smoking at 4 weeks and only the latter two mediated abstinence at 6 months (indirect mediating effects P < 0.05).

CONCLUSIONS

Nicotine pre-loading appears to facilitate smoking abstinence by reducing urges to smoke and smoke intake before quitting and urges to smoke after quitting.

Effects on abstinence of nicotine patch treatment before quitting smoking: parallel, two arm, pragmatic randomised trial

OBJECTIVE

To examine the effectiveness of a nicotine patch worn for four weeks before a quit attempt.

DESIGN

Randomised controlled open label trial.

SETTING

Primary care and smoking cessation clinics in England, 2012-15.

PARTICIPANTS

1792 adults who were daily smokers with tobacco dependence. 899 were allocated to the preloading arm and 893 to the control arm.

INTERVENTIONS

Participants were randomised 1:1, using concealed randomly permuted blocks stratified by centre, to either standard smoking cessation pharmacotherapy and behavioural support or the same treatment supplemented by four weeks of 21 mg nicotine patch use before quitting: "preloading."

MAIN OUTCOME MEASURES

The primary outcome was biochemically confirmed prolonged abstinence at six months. Secondary outcomes were prolonged abstinence at four weeks and 12 months.

RESULTS

Biochemically validated abstinence at six months was achieved by 157/899 (17.5%) participants in the preloading arm and 129/893 (14.4%) in the control arm: difference 3.0% (95% confidence interval -0.4% to 6.4%), odds ratio 1.25 (95% confidence interval 0.97 to 1.62), P=0.08 in the primary analysis. There was an imbalance between arms in the frequency of varenicline use as post-cessation treatment, and planned adjustment for this gave an odds ratio for the effect of preloading of 1.34 (95% confidence interval 1.03 to 1.73), P=0.03: difference 3.8% (0.4% to 7.2%). At four weeks, the difference in prolonged abstinence unadjusted for varenicline use was odds ratio 1.21 (1.00 to 1.48), difference 4.3% (0.0% to 8.7%), P=0.05, and adjusted for varenicline use was 1.32 (1.08 to 1.62) P=0.007. At 12 months the odds ratio was 1.28 (0.97 to 1.69), difference 2.7% (-0.4% to 5.8%), P=0.09 unadjusted for varenicline use and after adjustment was 1.36 (1.02 to 1.80) P=0.04. 5.9% of participants discontinued preloading owing to intolerance. Gastrointestinal symptoms-chiefly nausea-occurred in 4.0% (2.2% to 5.9%) more people in the preloading arm than control arm. Eight serious adverse events occurred in the preloading arm and eight in the control arm (odds ratio 0.99, 0.36 to 2.75).

CONCLUSIONS

Evidence was insufficient to confidently show that nicotine preloading increases subsequent smoking abstinence. The beneficial effect seems to have been masked by a concurrent reduction in the use of varenicline in people using nicotine preloading, and future studies should explore ways to mitigate this unintended effect.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN33031001.

Toward precision smoking cessation treatment II: Proximal effects of smoking cessation intervention components on putative mechanisms of action

BACKGROUND

Understanding how smoking cessation treatments exert their effects can inform treatment development and use. Factorial designs allow researchers to examine whether multiple intervention components affect hypothesized change mechanisms, and whether the affected mechanisms are related to cessation.

METHODS

This is a secondary data analysis of smokers recruited during primary care visits (N=637, 55% women, 87% white) who were motivated to quit. Participants in this fractional factorial experiment were randomized to one level of each of six intervention factors: Prequit Nicotine Patch vs None, Prequit Nicotine Gum vs None, Preparation Counseling vs None, Intensive In-Person Counseling vs Minimal, Intensive Phone Counseling vs Minimal, and 16 vs 8 Weeks of Combination Nicotine Replacement (nicotine patch+nicotine gum). Data on putative mechanisms (e.g., medication use, withdrawal, self-efficacy) and smoking status were gathered using daily assessments and during follow-up assessment calls.

RESULTS

Some intervention components influenced hypothesized mechanisms. Prequit Gum and Patch each reduced prequit smoking and enhanced prequit coping and self-efficacy. In-Person Counseling increased prequit motivation to quit, postquit self-efficacy, and postquit perceived intratreatment support. Withdrawal reduction and reduced prequit smoking produced the strongest effects on cessation. The significant effect of combining Prequit Gum and In-Person Counseling on 26-week abstinence was mediated by increased prequit self-efficacy.

CONCLUSIONS

This factorial experiment identified which putative treatment mechanisms were influenced by discrete intervention components and which mechanisms influenced cessation. Such information supports the combined use of prequit nicotine gum and intensive in-person counseling as cessation interventions that operate via increased prequit self-efficacy.