Frederique M. Behm

Mecamylamine combined with nicotine skin patch facilitates smoking cessation beyond nicotine patch treatment alone

To evaluate concurrent administration of mecamylamine (nicotine antagonist) with nicotine skin patch treatment for smoking cessation.

Arterial nicotine kinetics during cigarette smoking and intravenous nicotine administration: implications for addiction

An understanding of drug addiction requires knowledge of the effective drug concentrations to which receptors in the nervous system are exposed. It has often been thought that smoking of abused substances such as nicotine or cocaine produces much higher drug concentrations in the arterial blood than those achieved following any other route of administration. However, to date no studies have sampled arterial blood following cigarette smoking with the rapidity necessary to evaluate this hypothesis. We measured arterial plasma nicotine concentrations in samples collected every 5 s from 13 cigarette smokers during cigarette smoking and during administration of nicotine by intravenous injections. Our results show that, for both routes of administration, concentrations of nicotine in arterial blood were more than 10 times lower than expected. Thus, the delivery of nicotine into arterial blood is substantially slower than would be predicted if nicotine were absorbed as rapidly as has generally been assumed. A plausible explanation of these results is that lung uptake of nicotine considerably slows the entry of nicotine into the systemic circulation, as has been shown for other amines. These results have significant implications for theories of addiction to nicotine as well as other drugs such as cocaine that may be subject to binding by lung tissue.

Nicotine-mecamylamine treatment for smoking cessation: The role of pre-cessation therapy.

The nicotinic antagonist mecamylamine was evaluated in a randomized smoking cessation trial. Four groups of participants (n = 20 per group) received nicotine plus mecamylamine, nicotine alone, mecamylamine alone, or no drug for 4 weeks before cessation. After the quit-smoking date, all subjects received nicotine plus mecamylamine treatment for 6 weeks. Nicotine skin patches (21 mg/24 hr) and mecamylamine capsules (2.5-5.0 mg twice per day) were used. Precessation mecamylamine significantly prolonged the duration of continuous smoking abstinence; abstinence rates at the end of treatment were 47.5% with mecamylamine and 27.5% without mecamylamine. Nicotine + mecamylamine reduced ad lib smoking, smoking satisfaction, and craving more than either drug alone. Moreover, the orthostatic decrease in blood pressure caused by mecamylamine was offset by nicotine. Mecamylamine before smoking cessation may be an effective adjunct to nicotine patch therapy.

Psychopharmacological interactions between nicotine and ethanol

Epidemiological, clinical, and laboratory evidence has shown a positive correlation between cigarette smoking and ethanol use, and previous studies suggest some commonality in the neural pathways mediating effects of nicotine and ethanol. In this study, the subjective and behavioral interactions among nicotine, ethanol, and the nicotinic antagonist mecamylamine were investigated. The main objectives were to determine how the rewarding effects of nicotine might be modified by ethanol, and to compare the effects of ethanol with those of a nicotinic antagonist (mecamylamine). A total of 48 smokers who regularly consumed alcoholic beverages participated in four laboratory sessions presenting a 2 (nicotine vs. denicotinized cigarette smoke)x2 (10 mg oral mecamylamine hydrochloride vs. placebo)x2 (ethanol.5 g/kg vs. placebo) design, with ethanol as a between-subjects factor. Dependent measures included blood alcohol concentration (BAC), as assessed by breath alcohol detector; subjective drug effects; and rate of ad lib smoking during a 2-hr period. Results showed that peak BAC averaged.03 g/dl in the ethanol condition. Ethanol potentiated some of the subjective rewarding effects of nicotine, including smoking satisfaction, stimulant as well as calming effects, and relief of craving for cigarettes. During the ad lib smoking period, mecamylamine decreased satisfaction associated with the nicotine-containing cigarettes; mecamylamine also induced smoking but only in the placebo ethanol condition. These results highlight the potent interaction between ethanol and nicotinic systems, and suggest that ethanol can potentiate the rewarding effects of nicotine as well as offset some of the effects of a nicotinic antagonist.

Transdermal nicotine facilitates smoking cessation

The efficacy of a transdermal nicotine patch in facilitation of smoking cessation was evaluated in a randomized double‐blind trial. Sixty‐five smokers who were highly dependent on cigarettes participated in the study, which included a behavioral smoking‐cessation program. The rates of continuous abstinence were significantly higher in the nicotine group both initially (55% versus 34%) and at 3 weeks (18% versus 6%). Certain smoking withdrawal symptoms, including negative affect and hypoarousal, were effectively relieved by the nicotine patch. There was a trend toward a reduction in cigarette craving, whereas hunger and habit withdrawal symptoms were not affected. The main side effect associated with the nicotine patch was skin irritation. These findings suggest that a nicotine skin patch may be a useful aid to smoking cessation; however, the combination of other techniques with nicotine replacement may provide a more effective treatment for symptoms such as craving for cigarettes.

Precessation Treatment with Nicotine Skin Patch Facilitates Smoking Cessation

Nicotine replacement therapy (NRT) is a well-established treatment to aid smoking cessation, and current products recommend using NRT only after quitting smoking. However, theoretical arguments and previous data support the hypothesis that precessation use of NRT might be useful in reducing dependence on inhaled nicotine and serve as a helpful prelude to smoking cessation. The present study explored the use of NRT for 2 weeks before a target quit-smoking date, during which subjects continued to smoke ad libitum. Three experimental conditions varied the nicotine delivery of the cigarettes smoked during these 2 weeks so that we could examine the effects of concurrent nicotine administration on compensatory smoking of low tar and nicotine cigarettes. Subjects smoked (a) their usual brands of cigarettes, (b) conventional low tar and nicotine cigarettes, or (c) denicotinized cigarettes. After the quit date, subjects received pharmacotherapy consisting of various doses of NRT (0, 21, or 42 mg/24-hr) in combination with the nicotinic antagonist mecamylamine (10 mg/day). Results showed that precessation nicotine patch treatment was associated with a significantly higher rate of continuous smoking abstinence at 4 weeks, regardless of cigarette condition. Ad libitum smoking before the target quit date was modulated by nicotine patch treatment, and compensatory increases in smoking low tar and nicotine cigarettes were prevented by concurrent use of nicotine patches. These results suggest that use of NRT before a target quit-smoking date deserves further evaluation as a possible smoking cessation treatment. Moreover, while nicotine patches were well tolerated when subjects smoked nicotine-containing cigarettes, the use of nicotine skin patches with reduced-nicotine cigarettes potentially offers the advantage of increased efficacy without introducing concern about toxic effects of excessive nicotine intake.

Role of nicotine dose and sensory cues in the regulation of smoke intake

We investigated the role of nicotine dose and sensory cues in the regulation of ad lib smoke intake. The smoking behavior of 12 adult male smokers was assessed in three conditions, presenting either high-nicotine cigarette smoke (high nicotine, high sensory), diluted cigarette smoke (low nicotine, low sensory), or an aerosol containing cigarette smoke constituents suspended in solution, which was low in nicotine, yet high in sensory impact. Subjects showed marked compensatory increases in smoking with the dilute smoke conditions, whereas they puffed and inhaled the aerosol to a similar extent as the high-nicotine cigarette. Thus, subjects regulated their smoking behavior to equate sensory intensity rather than nicotine intake. Moreover, the aerosol and high-nicotine cigarette conditions lowered craving to a greater degree than the dilute smoke condition. Other mood indices, such as arousal and negative affect, were more effectively relieved by the high-nicotine dose condition. These results highlight the importance of sensory cues in the regulation of smoke intake and modulation of craving and suggest the clinical application of techniques for providing relief of cigarette craving during smoking cessation.

Personalized smoking cessation: interactions between nicotine dose, dependence and quit-success genotype score.

Improving and targeting nicotine replacement therapy (NRT) are cost-effective strategies for reducing adverse health consequences for smokers. Treatment studies document the efficacy of precessation NRT and support important roles for level of nicotine dependence and precessation smoking reduction in successful quitting. However, prior work has not identified the optimal precessation dose or means for personalizing NRT. Genome-wide association has identified groups of genomic markers associated with successful quitting, allowing us to develop a v1.0 “quit-success” genotype score. We now report influences of v1.0 quit-success genotype score, level of dependence and precessation smoking reduction in a smoking cessation trial that examined effects of 21 versus 42 mg/24 h precessation NRT. Four hundred seventy-nine smokers were randomized to 21 or 42 mg NRT, initiated 2 wks prior to target quit dates. We monitored self-reported abstinence and end-expired air carbon monoxide (CO). Genotyping used Affymetrix arrays (Santa Clara, CA, USA). The primary outcome was 10-wk continuous smoking abstinence. NRT dose, level of nicotine dependence and genotype scores displayed significant interactive effects on successful quitting. Successful abstinence also was predicted by CO reductions during precessation NRT. These results document ways in which smoking cessation strategies can be personalized based on levels of nicotine dependence, genotype scores and CO monitoring. These assessments, taken together, can help match most smokers with optimal NRT doses and help rapidly identify some who may be better treated using other methods.

Extinguishing the rewarding value of smoke cues: Pharmacological and behavioral treatments

The present study examined several pharmacological and behavioral treatments designed to promote extinction of the responses to rewarding cigarette smoke cues. Pharmacological treatments comprised nicotine skin patches (21 mg/24 hr) and the nicotinic acetylcholine receptor antagonist mecamylamine (10 mg/day), administered separately or in combination. Behavioral manipulations included switching to denicotinized cigarettes, to cigarettes having different menthol flavor, or to ventilated-filter (low tar and nicotine) cigarettes. Smokers were assigned to the various treatments for 2 weeks before they quit smoking. During weekly test sessions, subjects rated the rewarding effects of their usual brands of cigarettes or cigarettes with different menthol content (mentholated vs. nonmentholated). Over the 2-week treatment period, all pharmacological treatments reduced ratings of reward for the usual-brand test cigarettes. Switching to smoking denicotinized cigarettes for 2 weeks similarly decreased rewarding effects of the usual-brand test cigarettes. Subjects also strongly preferred cigarettes with the same menthol content to which they were accustomed. However, manipulating the menthol content of the cigarettes smoked during the 2 weeks of treatment had different effects, depending on whether smokers habitually smoked mentholated or nonmentholated cigarettes. For menthol smokers, removal of the menthol cue hampered extinction of reward ratings for the usual-brand (mentholated) test cigarette. For nonmenthol smokers, addition of the menthol cue did not affect the progress of extinction of nonmenthol smoke cues. These findings demonstrate the importance of sensory cues in determining subjective reward and show that the reward value of these cues can be altered by removal of nicotine from tobacco or by pharmacological manipulations that interfere with the reinforcing effects of nicotine.

Selectively reduced responses to smoking cues in amygdala following extinction-based smoking cessation: results of a preliminary functional magnetic resonance imaging study.

Preliminary studies suggest an extinction‐based smoking cessation treatment using reduced nicotine content (RNC) cigarettes decreases self‐report craving for cigarettes prior to quitting and may be an effective smoking cessation treatment. The aims of this study was to evaluate the effect of an extinction‐based smoking cessation treatment on brain responses to smoking cues using blood‐oxygen level‐dependent (BOLD) functional magnetic resonance imaging (fMRI). Sixteen (n = 16) dependent smokers were scanned using BOLD fMRI at baseline, following 2–4 weeks of smoking RNC cigarettes while wearing a 21‐mg nicotine patch, and 2–4 weeks following quitting smoking. During scanning, participants viewed smoking‐related pictures (e.g. lit cigarette) and pictures of people engaged in everyday activities (e.g. using a stapler). Event‐related BOLD responses to smoking and control cues were analyzed in regions of interest (ROIs) known to subserve reward, attention, motivation and emotion. The extinction‐based treatment simultaneously attenuated responses to smoking cues in amygdala while potentiating responses to control cues. Exploratory analysis indicated that this pattern was also observed in the thalamus of future abstinent but not relapsing smokers. The results of this preliminary study suggest that an extinction‐based treatment for smoking cessation alters brain responses to smoking and control cues in amygdala—a region previously associated with drug cue reactivity and extinction.