Bupropion and naltrexone for smoking cessation: A double-blind randomized placebo-controlled clinical trial

Combination of non-nicotine pharmacotherapies has been underexamined for cigarette smoking cessation. A randomized, double-blind, parallel-group double-dummy study evaluated two medications, bupropion (BUP) and naltrexone (NTX), in treatment-seeking cigarette smokers (N = 121) over a 7-week treatment intervention with 6-month follow-up. Smokers were randomized to either BUP (300 mg/day) + placebo (PBO) or BUP (300 mg/day) + NTX (50 mg/day). The primary outcome was biochemically verified (saliva cotinine, carbon monoxide) 7-day, point-prevalence abstinence. BUP + NTX was associated with significantly higher point-prevalence abstinence rates after 7-weeks of treatment (BUP + NTX, 54.1%; BUP + PBO, 33.3%), P = 0.0210, but not at 6-month follow-up (BUP + NTX, 27.9%; BUP + PBO, 15.0%), P = 0.09. Continuous abstinence rates did not differ, P = 0.0740 (BUP + NTX, 26.2%; BUP + PBO, 13.3%). Those receiving BUP + NTX reported reduced nicotine withdrawal, P = 0.0364. The BUP + NTX combination was associated with elevated rates of some side effects, but with no significant difference in retention between the groups.

Immunogenicity and smoking-cessation outcomes for a novel nicotine immunotherapeutic

NicVAX^®, a nicotine vaccine (3’AmNic-rEPA), has been clinically evaluated to determine if higher antibody concentrations are associated with higher smoking abstinence rates and if doses and frequency of administration are associated with increased antibody response. This randomized, double-blinded, placebo-controlled multicenter clinical trial (N=301 smokers) tested 200 and 400 µg doses administered 4 or 5 times over 6 months compared to placebo. 3’AmNic-rEPA recipients with the highest serum anti-nicotine antibody response (top 30% by AUC) were significantly more likely to attain 8 weeks continuous abstinence from weeks 19 through 26 than the placebo recipients (24.6% vs. 12.0%, p=0.024, OR=2.69, 95% CI, 1.14–6.37). The 5 injection 400 µg dose regimen had the greatest antibody response and had significantly higher abstinence rates than placebo. This study demonstrates proof-of-concept that 3’AmNic-rEPA elicits antibodies to nicotine and is associated with higher continuous abstinence rates, justifying its further development as a treatment for nicotine dependence.

Exposure to nicotine and a tobacco-specific carcinogen increase with duration of use of smokeless tobacco

BACKGROUND

Smokeless tobacco is an efficient delivery vehicle for nicotine and can contain significant amounts of carcinogens. However, few studies have examined factors that might moderate levels of nicotine or carcinogen exposure.

AIMS

To determine the effect of duration of smokeless tobacco use on the uptake of nicotine and a tobacco-specific carcinogen, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK).

METHODS

Questionnaires on use of smokeless tobacco were administered, and urine samples from 212 smokeless tobacco users were analysed for biomarkers of uptake of nicotine and NNK. The biomarkers were cotinine and total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). Male smokeless tobacco users were recruited for studies designed to investigate methods of reducing smokeless tobacco use. The questionnaire and biomarker data were obtained at baseline, prior to reduction.

RESULTS

Levels of cotinine (p<0.001) and total NNAL (p<0.001) were significantly correlated with duration (in years) of use of smokeless tobacco products. Median cotinine and total NNAL were 2.4 and 2.1 times higher, respectively, in the > or = 21 years of use than in the 0-5 years of use category.

CONCLUSIONS

Smokeless tobacco users adjust their intensity of use with experience in order to increase their nicotine dose, resulting in a corresponding increase in exposure to NNK, a powerful carcinogen. These results indicate the importance of educating smokeless tobacco users about the effects of prolonged use of these products.

Smokeless tobacco brand switching: a means to reduce toxicant exposure?

The purpose of this study was to examine the effects of smokeless tobacco (ST) brand switching on biomarkers of ST exposure and on ST use. Subjects seeking treatment to reduce their use were randomized to ST brand switching with controlled ST topography, brand switching with ad libitum ST use, or a waitlist control with subsequent randomization to one of these two conditions. The waitlist control group was included to assess whether changes were a consequence of time effect. During the intervention, Copenhagen or Kodiak ST users were asked to switch to products that were sequentially lower in nicotine content: Skoal Long Cut Straight or Wintergreen for 4 weeks and then Skoal Bandits for the subsequent 4 weeks. Measures were obtained during the course of treatment and at 12-week follow-up. Significant reductions in total urinary cotinine and 4-(methylnitrosamino)-L-(3-pyridyl)-L-butanol (NNAL) plus its glucuronides (total NNAL) were observed with no significant differences between the controlled topography and ad libitum conditions. Significant reductions were also observed in the amount and duration of dips with a significant intervention effect for durational measures. At 12 weeks, the 7-day biochemically-verified tobacco abstinent rate was 26% in the ad libitum group. ST brand switching may be a feasible alternative intervention for ST users interested in quitting but unwilling to stop ST use completely.

Biomarkers of tobacco exposure or harm: application to clinical and epidemiological studies. 25-26 October 2001, Minneapolis, Minnesota

Adverse outcomes from tobacco use may take decades to develop. Biomarkers are measures that can be used in the early stages of tobacco use to assess exposure to tobacco toxins or to predict adverse health outcomes with which they are associated. Examples of biomarkers include specific chemical components of tobacco or their metabolites; early biochemical, histological, or physiological effects; and early health effects. Mechanistically relevant and quantitatively valid biomarkers are essential for assessing the ultimate impact of new products, treatments, preventive measures, and public health policies on tobacco-related disease. The tobacco industry's recent introduction of a variety of new tobacco products or devices with implied claims of reduced health risks highlights the need to develop methods for assessing their potential for benefit or harm. A wide variety of biomarkers for tobacco exposure or harm has been studied. Although many questions about their use remain unanswered, substantial data exist regarding their validity and utility. This conference reviewed both the general issues surrounding biomarker use and the current state of knowledge regarding the most widely studied and promising biomarkers.

Targeting treatments to special populations

The average rate of long-term tobacco abstinence in a general population of treatment-seeking tobacco users is about 25%. Most of these treatments tend to use generic approaches, although the population of tobacco users is quite heterogeneous. It is entirely possible that special populations of smokers have specific treatment needs. If these needs are addressed, then treatment success may be augmented. This paper will review different issues that may surface when treating special populations. The special populations to be examined will be broken down by gender, age and route of tobacco administration. In addition, gaps in the scientific literature and directions for future research will be discussed. Once population-specific treatment needs are identified, then the effects of tailored treatments in augmenting treatment success can be determined.

Effect of nonnicotine pharmacotherapy on smoking behavior

Smoking-related disease is the single biggest preventable cause of morbidity and mortality in the United States, yet approximately 25% of Americans continue to smoke. Various dosage forms of nicotine replacement therapy increase smoking quit rates relative to placebo, but they generally do not result in 1-year quit rates of over 20%. To increase these rates, a number of nonnicotine agents have been investigated. Drugs that modulate noradrenergic neurotransmission (bupropion, nortriptyline, moclobemide) are more effective than those affecting serotonin (selective serotonin reuptake inhibitors, buspirone, ondansetron) or other neurotransmitters.

Depressive symptoms modulate the subjective and physiological response to cocaine in humans

The goal of this study was to examine the relationship between the presence of subclinical depressive symptoms and physiological and subjective responses to smoked cocaine in humans. Cocaine users without major depression, who participated in various inpatient studies, received a single 0.4 mg/kg of smoked cocaine. When the relationship between the Beck Depression Inventory (BDI) scores and various subjective and physiological responses to cocaine was examined, similar trends were found. Low BDI scores of 0-7 were associated with a smaller physiological and subjective cocaine response. In contrast, BDI ranges of 8-13 were associated with enhanced cocaine response which plateaued or declined in the higher (> 14) BDI group. These group differences were not explained by sex or body weight differences among groups. The implication of these results is that the presence of depressive symptoms may affect cocaine use behavior partly by being associated with an enhanced response to cocaine.

Progesterone treatment during the early follicular phase of the menstrual cycle: effects on smoking behavior in women

The goals of this study were (1) to examine the feasibility of administering progesterone to women during the early follicular phase when the endogenous estradiol and progesterone levels are low, and (2) to investigate the effects of oral progesterone treatment on smoking behavior in female smokers. Twelve subjects had two experimental sessions, within 3-9 days after the beginning of their menses. In each experimental session, subjects received a single 200-mg dose of progesterone or placebo, orally. Two and a half hours after the medication treatment, subjects were assessed for subjective response to two puffs of a cigarette and then started the self-administration period in which they had the option to exchange their token for two puffs of cigarette, 15 min apart. Subjects had low levels of estradiol and progesterone before the first and second sessions. Plasma progesterone levels peaked in 2 h following progesterone treatment. Progesterone treatment attenuated the craving for and subjective effects from smoking. Under progesterone treatment, there was a trend for decreased smoking behavior. These preliminary results suggest that the early follicular phase of the menstrual cycle may be a useful interval to investigate the effects of exogenous progesterone in female smokers. The effects of progesterone on nicotine dependence need to be studied further.

Intravenous cocaine increases plasma epinephrine and norepinephrine in humans

Cocaine has been shown to activate the sympathoadrenal system in both animal and human studies. Controlled human studies have found inconclusive results regarding whether acute cocaine treatment elevates plasma epinephrine and norepinephrine concentrations. The purpose of this study was to investigate whether commonly abused doses of cocaine increase plasma epinephrine and norepinephrine concentrations in humans, in a double-blind, placebo-controlled study. Five male cocaine users were given an intravenous injection of 0.46 mg/kg dose of cocaine or placebo, on two consecutive days. Plasma epinephrine and norepinephrine concentrations were significantly increased in response to cocaine injection compared to placebo. Peak plasma epinephrine and norepinephrine concentrations were reached 3 and 12 min after cocaine injection, respectively. While changes in epinephrine levels following cocaine were correlated with systolic blood pressure and heart rate changes, changes in plasma norepinephrine were correlated with diastolic blood pressure and heart rate changes following cocaine administration. These results suggest that plasma epinephrine and norepinephrine can be used as a measure for cocaine induced sympathoadrenal system activation.

Acute abstinence effects following smoked cocaine administration in humans

Acute abstinence symptomatology following multiple deliveries of smoked cocaine was examined. Twelve crack cocaine users (male and female) participated in an inpatient study. Participants smoked 7 deliveries of cocaine on each of 4 experimental days, with each participant being exposed twice to 2 dose sizes of cocaine (0.40 vs. 0.07 mg/kg "placebo"). Symptoms of cocaine abstinence were measured for 6 hr following cocaine administration and again the following morning. Participants reported feeling increased craving, anxiety, and uncertainty 30 min after the 7th delivery of 0.40 mg/kg cocaine, when cocaine plasma levels were still on the descending curve. It is not clear whether these were true abstinence effects or were due to residual effects of cocaine. No significant differences were found at subsequent abstinence-assessment points. These data indicate that acute abstinence effects from smoked cocaine in a laboratory setting may be minimal.

Individual differences in the subjective response to smoked cocaine in humans

The individual variables that determine the effects of cocaine in humans are not well understood. In this study, we examined the relationship between the subjective response to cocaine and selected individual variables in cocaine-dependent participants. A single 0.4-mg/kg dose of smoked cocaine was received by 75 smoked cocaine users. The variables associated with increased subjective response to cocaine were male sex, presence of alcohol use, higher baseline Beck Depression Inventory (BDI) scores, and duration of cocaine use. The change in heart rate and diastolic blood pressure in response to cocaine delivery were also positively associated with the subjective response to cocaine. In contrast, body weight, years of schooling, and the change in the heart rate with the expectation of cocaine delivery were associated with a diminished subjective response to cocaine. The importance of these variables in maintaining the cocaine use behavior needs to be studied further.

Characteristics of research volunteers for inpatient cocaine studies: focus on selection bias

In order to investigate the selection bias of subjects for inpatient human cocaine studies, characteristics of 859 potential subjects were examined. Excluded subjects compared with accepted group were more likely to be single and male, currently use drugs other than cocaine, have a history of intravenous cocaine use, and have medical or mental health problems or physical complaints. Subjects who were accepted but did not participate, compared with participants, were likely to spend more money on cocaine. These results suggest that potential subjects who were accepted to our research studies may not accurately represent all potential subjects for several important subject characteristics.

Carvedilol affects the physiological and behavioral response to smoked cocaine in humans

The noradrenergic system is implicated in mediating some of the physiological effects of cocaine. The purpose of this study was to investigate whether treatment with an adrenergic blocker, carvedilol, which would be expected to attenuate the physiological effects of cocaine, would also attenuate the subjective and behavioral response to cocaine in humans. Twelve crack cocaine users participated in this double-blind, placebo-controlled outpatient study. Acute treatment with 50 mg of oral carvedilol attenuated the smoked cocaine-induced increases in heart rate, systolic and diastolic blood pressure. The number of cocaine self-administrations was lower under 25 mg carvedilol treatment condition compared with 50 mg carvedilol or placebo treatment conditions. The subjective responses to smoked cocaine deliveries were not affected by carvedilol treatment. These results suggest that acute treatment with carvedilol attenuates the physiological effects of smoked cocaine. The effects of carvedilol on cocaine self-administration need to be studied further.

Treatment of spit tobacco users with transdermal nicotine system and mint snuff

The purpose of this study was to examine the effects of nicotine patch and mint snuff (a nonnicotine product) on craving, withdrawal symptoms, and treatment outcome. This study involved a 2 x 2 factorial design, with Active Nicotine Versus Placebo Patch as one of the factors and Mint Snuff Versus No Mint Snuff as the other factor. Spit tobacco users (N = 402, n = 100-101 in each condition) were randomly assigned to 1 of the 4 treatment conditions for a period of 10 weeks. Treatment outcome was measured up to 62 weeks. The results showed that the nicotine patch was effective in increasing short-term abstinence over the placebo patch and in reducing craving and withdrawal signs and symptoms from spit tobacco. Although mint snuff was not effective in enhancing treatment outcome, it reduced craving and withdrawal symptoms. No interaction effects were observed. At this time, the use of the nicotine patch and mint snuff should be primarily considered for the reduction of craving and withdrawal symptoms.

Effects of labetalol treatment on the physiological and subjective response to smoked cocaine

Adrenergic receptors mediate some of the physiological and possibly behavioral effects of cocaine. The purpose of this study was to investigate the effect of treatment with a peripherally acting adrenergic blocking drug labetalol on the cardiovascular and subjective response to repeated deliveries of smoked cocaine. In this double-blind, placebo-controlled, crossover study, 12 cocaine users were treated with a single 100 or 200 mg dose of labetalol, or placebo in each of three experimental sessions. Starting 2 h after the medication treatment, subjects received three doses of 0.4 mg/kg smoked cocaine, 30 min apart. Labetalol treatment significantly attenuated the cocaine-induced increases in heart rate and systolic blood pressure. This effect of labetalol on the cardiovascular response did not decrease with repeated cocaine deliveries. The subjective response to smoked cocaine deliveries was not affected by labetalol treatment. These results suggest that labetalol effectively attenuates the systolic blood pressure and heart rate increases induced by repeated doses of smoked cocaine, but does not alter subjective effects.

Predictors of cardiovascular response to smoked cocaine in humans

The purpose of this study was to examine the predictors of heart rate and blood pressure changes following cocaine administration. Sixty-two smoked cocaine users received a single 0.4 mg/kg dose of smoked cocaine. Male sex, African American race, higher body weight and current marijuana use predicted a greater cardiovascular response to cocaine. In contrast, higher baseline blood pressure, heart rate, amount and frequency of current cocaine use and presence of current cocaine snorting predicted a diminished cardiovascular response to cocaine. Whether these predictors of the cardiovascular response to smoked cocaine in the laboratory also predict cardiovascular complications from long-term cocaine use needs to be studied further.

Sex and menstrual cycle differences in the subjective effects from smoked cocaine in humans

To investigate sex and menstrual cycle effects in response to cocaine administration, data from existing studies were analyzed. First, responses to a single delivery of 0.4 mg/kg smoked cocaine were investigated. Women reported lower ratings for measures of paranoid/suspicious and heart racing/pounding than did men. In addition, women in the luteal phase reported diminished ratings for a measure of feel high than did both women in the follicular phase of the menstrual cycle and men. Second, responses to up to 6 deliveries of 0.4 mg/kg smoked cocaine were investigated. Women, compared with men, had lower ratings on feel high, heart racing/pounding, and feel stimulated. Results suggest that there are significant sex and menstrual phase differences in the subjective effects of cocaine.

Sex and menstrual cycle differences in the subjective effects from smoked cocaine in humans

To investigate sex and menstrual cycle effects in response to cocaine administration, data from existing studies were analyzed. First, responses to a single delivery of 0.4 mg/kg smoked cocaine were investigated. Women reported lower ratings for measures of paranoid/suspicious and heart racing/pounding than did men. In addition, women in the luteal phase reported diminished ratings for a measure of feel high than did both women in the follicular phase of the menstrual cycle and men. Second, responses to up to 6 deliveries of 0.4 mg/kg smoked cocaine were investigated. Women, compared with men, had lower ratings on feel high, heart racing/pounding, and feel stimulated. Results suggest that there are significant sex and menstrual phase differences in the subjective effects of cocaine.

Characteristics of smokeless tobacco users seeking treatment

Previous studies have described smokeless tobacco (ST) treatment seekers with minimal detail. In the present study, ST users (N = 402), who enrolled in a ST cessation treatment study, were asked to complete an extensive questionnaire that inquired about their ST use patterns, use of other tobacco products, extent of dependence, previous attempts to quit, situations associated with use and support for quitting. The results showed that this population experiences a high level of nicotine exposure and physical dependence on ST. ST use frequently is associated with negative affect situations and times of hunger. A high frequency of users have smoked cigarettes as well as cigars. A supportive social environment for ST cessation exists for these individuals. These results have implications for ST treatment content.

Withdrawal and pre-menstrual symptomatology during the menstrual cycle in short-term smoking abstinence: effects of menstrual cycle on smoking abstinence

This study employs a rigorous inpatient laboratory setting to test the hypothesis that withdrawal symptomatology in short-term smoking cessation in women is increased in the late luteal phase when pre-menstrual symptomatology is the highest. Twenty-one female smokers with clinical, anatomical, and hormonal verification of their menstrual cycle phase were randomized to either a smoking abstinence group (n = 16) or a continued smoking group (n = 5). Participants were admitted to the General Clinical Research Center during alternate phases of their cycle for two 7-day admissions with a 1-month interim period when they resumed smoking. Dependent measures, i.e., Minnesota Nicotine Withdrawal Scale scores, Questionnaire on Smoking Urges scores and Pre-menstrual Assessment Form scores were collected during 2 days of baseline and 5 days of smoking deprivation. Smoking behavior was documented by self-report, breath CO levels and saliva cotinine measurements. Withdrawal symptomatology was not affected by menstrual cycle phase during short-term cessation in spite of increased pre-menstrual changes seen in the late luteal phase. In addition, no phase effect on smoking behavior was detected and cigarette consumption remained stable across the cycle in both groups. These results suggest that for some smoking cessation studies, complex strategies to control for menstrual cycle effects may not be necessary. However, Smoking Urges scores did suggest increased desire to smoke and desire to relieve negative affect in the late luteal phase when women have higher pre-menstrual symptomatology. This suggests women may have greater difficulty quitting smoking in late luteal phase, and it seems prudent to recommend that women quit during the follicular phase of their cycle.

Are higher doses of nicotine replacement more effective for smoking cessation?

This study determined whether higher dose nicotine patches are more efficacious than lower dose patches among heavy smokers. A randomized double-blind study compared 0, 21, 35, and 42 mg/day of a 24-h patch in 1039 smokers (> or = 30 cigarettes/day) at 12 clinical sites in the USA and one in Australia. Daily patches were used for 6 weeks followed by tapering over the next 10 weeks. Weekly group therapy occurred. Biochemically validated self-reported quit rates at 6, 12, 26, and 52 weeks post-cessation were measured. Quit rates were dose-related at all follow-ups (p < 0.01). Continuous, biochemically verified abstinence rates for the 0, 21, 35, and 42 mg doses at the end of treatment (12 weeks) were 16, 24, 30, and 39%. At 6 months, the rates were 13, 20, 20, and 26%. Among the 11 sites with 12 month follow-up (n = 879), the quit rates were 7, 13, 9, and 19%. In post-hoc tests, none of the active doses were significantly different from each other at any follow-up. The rates of dropouts due to adverse events for 0, 21, 35, and 42 mg were 3, 1, 3, and 6% (p = n.s.). Our results are similar to most prior smaller studies; i.e., in heavy smokers higher doses increase quit rates slightly. Longer durations of treatment may be necessary to show greater advantages from higher doses.

Oral spit tobacco: addiction, prevention and treatment

The prevalence of smokeless tobacco is significant and reaches as high as 17% past month use in white males aged 18-25. Smokeless tobacco use is of concern because of the potential for addiction and the associated negative health consequences. This article reviews the basis for addiction to smokeless tobacco, examining the nicotine content in smokeless tobacco products, pharmacokinetics, psychoactive effects, tolerance, and withdrawal. It also explores the negative health consequences which include a number of oral pathologies and increased cardiovascular risk factors. Furthermore, it examines the factors associated with the initiation of smokeless tobacco use, and the current prevention programs that address these factors. Current smokeless tobacco treatment approaches are also discussed as well as predictors for abstinence. Finally, the future directions are discussed in light of the limited amount of research that has been conducted in the smokeless tobacco area, particularly related to prevention and treatment.

Effects of phenytoin on cocaine self-administration in humans

The goal of this pilot study was to determine the effects of phenytoin on cocaine self-administration in a human laboratory model. Subjects were randomized to either phenytoin (n = 6) or placebo (n = 7). Those assigned to phenytoin treatment received a single oral loading dose of 20 mg/kg. The phenytoin and placebo treatment groups did not differ in the number of tokens valued at $5, exchanged for cocaine. Similarly, the cardiovascular and subjective response to cocaine administration did not show a statistically significant treatment effect. In this laboratory model, phenytoin did not alter either the self-administration or effects of cocaine.

Quantitation of 4-oxo-4-(3-pyridyl)butanoic acid and enantiomers of 4-hydroxy-4-(3-pyridyl)butanoic acid in human urine: A substantial pathway of nicotine metabolism

A liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC-APCI-MS/MS) method was developed to analyze human urine for 4-oxo-4-(3-pyridyl)butanoic acid (keto acid) and the enantiomers of 4-hydroxy-4-(3-pyridyl)butanoic acid (hydroxy acid) to test our hypothesis that (S)-hydroxy acid could be a biomarker of metabolic activation of the tobacco-specific carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) while (R)-hydroxy acid would be formed predominantly from nicotine, as indicated by studies with rats. Urine was collected from smokers, and from the same individuals after they had stopped smoking and used a nicotine transdermal system (nicotine patch) for 3 weeks. If (S)-hydroxy acid were a biomarker of NNK and NNN metabolic activation, its levels should be higher in the urine of smokers than in nicotine patch users because tobacco smoke, but not the nicotine patch, contains NNK and NNN. Internal standard, [2,2,3,3,4-D5]hydroxy acid, was added to an aliquot of urine, which was then subjected to solid phase extraction. The eluant containing hydroxy acid was esterified with acidic methanol, followed by treatment with (S)-(-)-alpha-methylbenzyl isocyanate, producing methyl-4(S)- or methyl-4(R)-[(S)-alpha-methylbenzylcarbamoyl]-4-(3-pyridyl)buta noate [(S,S)- or (R,S)-MMPB, respectively]. After HPLC purification, the MMPB diastereomers were separated and quantified by LC-APCI-MS/MS. Mean levels of (S)- and (R)-hydroxy acid were 14.1 +/- 8.0 and 1120 +/- 600 ng/mL, respectively, in smokers during ad lib smoking (n = 18), while the corresponding levels during nicotine patch use (n = 18) were 4.1 +/- 3.3 and 363 +/- 228 ng/mL. The amounts of (S)-hydroxy acid were far higher than could be formed from NNK and NNN, and the total amount of hydroxy acid indicated that it was a substantial urinary metabolite of nicotine, in contrast to results with rats. Therefore, the study was extended to quantify keto acid. This was accomplished by NaBH4 treatment of urine, which converted keto acid to hydroxy acid quantitatively, which was in turn analyzed as described above. Levels of keto acid while subjects were smoking and using the nicotine patch were 228 +/- 129 (n = 8) and 97.5 +/- 80.6 ng/mL (n = 8), respectively. These results indicate that conversion of nicotine to keto acid and hydroxy acid is a substantial metabolic pathway in humans, accounting for an estimated 14% of the nicotine dose. Apparently, keto acid is extensively converted to hydroxy acid in humans, in contrast to the results with rats. (S)-Hydroxy acid in human urine cannot be used as a biomarker of NNK and NNN metabolic activation because it is overwhelmed by the (S)-hydroxy acid formed from nicotine, despite the fact that >98% of the urinary hydroxy acid has the (R)-configuration. These results provide new insights about nicotine metabolism in humans.

The smoking cessation efficacy of varying doses of nicotine patch delivery systems 4 to 5 years post-quit day

BACKGROUND

This study was undertaken to evaluate the long-term smoking cessation efficacy of varying doses of transdermal nicotine delivery systems 4 to 5 years post-quit day.

METHODS

A follow-up study was conducted 48 to 62 months after quit day among patients who were enrolled in the Transdermal Nicotine Study Group investigation. The latter study included group smoking cessation counseling and randomized assignment to 21, 14, or 7 mg nicotine patches or placebo patches. Seven of nine smoking cessation research centers participated in the long term follow-up investigation.

RESULTS

The self-reported continuous quit rate among patients originally assigned 21 mg (20.2%) was significantly higher than rates for patients assigned 14 mg (10.4%), 7 mg (11.8%), or placebo patches (7.4%). Log rank survival analysis found no difference in relapse rates after 1 year postcessation. Smokers under age 30 years were significantly less likely to be abstinent at long term follow-up compared to smokers > or = 30 years of age (3 vs 13%, respectively). Mean weight gain in confirmed continuous quitters was 10.1 kg in men and 8.0 kg in women. Of the 63 continuous abstainers surveyed, 30 respondents (48%) reported that they no longer craved cigarettes, and no individual reported daily craving for cigarettes.

CONCLUSIONS

Nicotine patch therapy with 21 mg/day patches resulted in a significantly higher long-term continuous abstinence rate compared to lower dose patches and placebo. Relapse rates among the various treatment conditions were similar after 1 year postcessation.

Quantitation of urinary metabolites of a tobacco-specific lung carcinogen after smoking cessation

We quantified urinary levels of two metabolites of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in people who had stopped smoking: 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its O-glucuronide, 4-[(methylnitrosamino)-1-(3-pyridyl)but-1-yl]-beta-O-D-glucosiduronic acid (NNAL-Gluc). Twenty-seven people completed the study. Thirteen used the nicotine patch starting at the quit date, whereas the others used no patch. Two 24-h urine samples were collected on 2 consecutive days before smoking cessation; blood was also obtained. Beginning at their quit date, subjects provided 24-h urine samples on days 7, 21, 42, 70, 98, and 126, and some subjects also provided samples at later times. The urine was analyzed for NNAL, NNAL-Gluc, nicotine plus nicotine-N-glucuronide, and cotinine plus cotinine-N-glucuronide. Some blood samples were also analyzed for NNAL. The decline of urinary NNAL and NNAL-Gluc after smoking cessation was much slower than expected. This was clearly demonstrated by comparison with cotinine and nicotine levels in urine. One week after smoking cessation, 34.5% of baseline NNAL plus NNAL-Gluc was detected in urine, whereas the corresponding values for cotinine and nicotine were 1.1 and 0.5%, respectively. Even 6 weeks after cessation, 7.6% of the original levels of NNAL plus NNAL-Gluc remained. In some subjects, NNAL plus NNAL-Gluc were detected 281 days after cessation. The distribution half-life for NNAL and NNAL-Gluc was 3-4 days, whereas the elimination half-life was 40-45 days. Total body clearance of NNAL was estimated to be 61.4 +/- 35.4 ml/min, and volume of distribution in the beta-phase was estimated to be 3800 +/- 2100 liters, indicating substantial distribution into the tissues. Parallel studies in rats treated chronically or acutely with NNK in the drinking water support the conclusion that NNAL has a large volume of distribution. There was no effect of the nicotine patch on levels of NNAL plus NNAL-Gluc, indicating that NNK is not formed endogenously from nicotine. The results of this study demonstrate that NNAL and NNAL-Gluc are slowly cleared from the body after smoking cessation, indicating the presence of a high-affinity compartment where NNK, NNAL, and/or NNAL-Gluc are retained or sequestered and slowly released.

Comparing i.v. and non-i.v. cocaine users. Characteristics of a sample of cocaine users seeking to participate in research

The authors examined differences between current intravenous (i.v.), past i.v., and no i.v. cocaine use among a sample of cocaine users on measures of drug use, medical history, psychiatric history, and criminal history. Past i.v. cocaine users were older than non-i.v. cocaine users. The current i.v. cocaine-using group included more white participants, and the non-i.v. group included more African Americans. Those with past or current i.v. use had more extensive drug use histories than non-i.v. users. Also, more current and past i.v. cocaine-using groups reported having been tested for HIV and reported testing positive for hepatitis. Former i.v. cocaine users reported more emergency room visits for complications stemming from cocaine use. They also reported more treatment for substance abuse and were convicted of more crimes. These results suggest that the route of administration is important in studying the characteristics of drug users.

Use of smokeless tobacco by young adult females

In contrast to the well documented use of smokeless tobacco (ST) by men, far less is known about ST use by women. In part this is due to the small overall prevalence of ST use among women (0.6%). This paper is a descriptive report of the use of ST by young adult women in the upper midwest. Twenty women, identified as smokeless tobacco users, completed a tobacco questionnaire and brief interview. The majority (80%) were introduced to ST by friends and 60% had tried cigarettes before using ST. Almost all used ST daily, averaging 3.6 dips per day. The number of dips per day was significantly correlated with salivary cotinine (r = .60). Subjects listed relaxation and pleasure most frequently as reasons for using ST. Twenty-five percent reported using ST to quit smoking and a similar percentage reported using ST to curb their appetite. With the introduction of new flavored snuff products, ST may become more appealing to the tastes of diverse groups including women. The potential acceptance of ST among women should be the focus of further research.

The role of tobacco cessation, antiplatelet and lipid-lowering therapies in the treatment of peripheral arterial disease

Despite the widely held belief that there are no effective medical therapies for peripheral arterial disease (PAD), current data suggest that medical therapies can effectively modify the natural history of atherosclerotic lower extremity arterial occlusive disease. The ideal medical therapy would improve claudication, forestall the onset of limb-threatening events, decrease rates of invasive interventional therapies and improve long-term patient survival. These ideal outcomes might be achieved through the use of smoking cessation interventions, including behavioral and pharmacological therapy, and the administration of antiplatelet and lipid-lowering medications in patients with PAD.

Variation in human plasma cholinesterase activity during low-dose cocaine administration

BACKGROUND

Cocaine is metabolized by a number of enzymes, the activity of one of which, plasma cholinesterase has been associated with dinical manifestations of toxicity. Patients with life-threatening complications of cocaine intoxication have lower plasma cholinesterase activity than less toxic controls. In addition, relatively healthy cocaine users have lower plasma cholinesterase activity than noncocaine using controls. Thus, low plasma cholinesterase activity could be a contributing factor to cocaine toxicity, a consequence of cocaine use, or a confounding variable. The following study was designed to further assess the relationship between cocaine use and plasma cholinesterase activity.

METHODS

We studied fluctuations in plasma cholinesterase activity in nine subjects enrolled in an inpatient study of the behavioral pharmacology of smoked cocaine. Subjects used at least 2 g of cocaine weekly for at least 1 year prior to enrollment. The subjects were admitted to the research unit where they remained drug-free for 2 days. They then received smoked cocaine for 4 days (up to 405 mg over 5 hours daily) and were then drug-free again for 2 days. Plasma cholinesterase activity was measured at 9 AM and 4 PM each day.

RESULTS

Baseline plasma cholinesterase ranged from 265 to 930 U/L (normal > 450 U/L). The mean plasma cholinesterase increased 112+/-100 U/L from day 1 to day 8 (p = 0.025). There was no daily change in plasma cholinesterase levels from 9 AM to 4 PM (15+/-165 U/L, p > 0.6), and there was no difference in the daily change between high- and low-dose cocaine days (-3+/-137 U/L vs 28+/-165 U/L, p = 0.52).

CONCLUSION

These preliminary data suggest that plasma cholinesterase levels do not change over a 7-hour period as a result of cocaine administration, but may increase during a period of inpatient study. Such an increase could potentially influence the pharmacokinetics or effects of cocaine studied in an inpatient setting and may give insight into the etiology of the observed low-plasma cholinesterase activity in cocaine users.

Effects of three doses of transdermal nicotine on post-cessation eating, hunger and weight

Smokers were randomly assigned to 0, 7, 14 or 21 mg doses of transdermal nicotine and had their eating and weight followed for 6 weeks. Among the 66 subjects who were abstinent for all 6 weeks, caloric, carbohydrate and fat intake, hunger, and weight increased in those on placebo, but alcohol, caffeine and protein intake did not. Nicotine patch decreased caloric, carbohydrate and fat intake in a dose-related manner, showed a trend for weight and showed no effect for hunger. Neither abstinence from smoking nor nicotine therapy shifted the percent of calories from sweets or carbohydrates. We conclude nicotine replacement reduces post-cessation increases in eating but does not have a specific effect on sweet intake.

Eating behavior and weight control among women using smokeless tobacco, cigarettes, and normal controls

Although considerable research has investigated the use of cigarette smoking for weight management, the potential role of smokeless tobacco (ST) use in dieting behavior has not been explored. Several measures designed to assess dieting behavior, attitudes toward eating, and tobacco use were administered to adult women using ST (n = 18), cigarettes (n = 20), and no tobacco (n = 20). Use of tobacco for weight loss was prevalent among the women smoking cigarettes. Nearly half the women in the cigarette-smoking group (45%) reported use of cigarettes to assist in weight loss, and only three (16.6%) of the women in the ST groups indicated use of ST for such purposes. No significant differences were observed across groups on measures of dietary restraint or attitudes toward eating. Issues of dieting and weight control may not be important factors in prompting ST use. Implications and areas for further research are discussed.

Effects of transdermal nicotine or smoking on nicotine concentrations and maternal-fetal hemodynamics

OBJECTIVE

To compare nicotine concentrations and fetal middle cerebral artery resistance indices (RIs) during 21-mg transdermal nicotine use with these values during maternal smoking.

METHODS

In this randomized, crossover study, participants smoked approximately 20 cigarettes daily and were between 24 and 36 weeks' gestation. Subjects were randomized to transdermal nicotine or to smoking ad libitum for 8 hours. One week later, they crossed over to the other condition. Maternal plasma nicotine concentrations and hemodynamic measurements were obtained before and after the onset of smoking or patch placement.

RESULTS

Area under the plasma nicotine concentration-time curve during patch use was similar to continued smoking (93 versus 89 ng-hour/mL, respectively) (P = .77). The mean (standard error [SE] change in the middle cerebral artery RI from baseline to 4 hours later was similar during patch use and smoking: -.002 (0.008) versus -.02 (0.015), respectively (P = .3). The study had greater than 80% power to detect a 25% difference in nicotine concentrations and a change of 2 standard deviations in the middle cerebral artery RI between conditions. An unexpected finding was that of a loss of fetal heart rate (FHR) reactivity in 5/8 tracings after patch placement versus 1/6 tracings after smoking (P = .12). The baseline FHR increased by a mean (SE) of 8 (4) beats per minute with loss of reactivity in the patch condition, compared with a decrease of 3 (3) beats per minute without loss of reactivity (P = .05).

CONCLUSION

Eight-hour use of 21-mg transdermal nicotine yields nicotine concentrations and middle cerebral artery RIs similar to those produced by hourly smoking in pregnant smokers.

Prevention and treatment of smokeless tobacco use

A review of the literature examining school-based prevention and treatment intervention programs for smokeless tobacco users is provided. Although few school-based prevention studies have been conducted, the results are promising. Many of the treatment studies that have been conducted, thus far, are limited due to the sample size and the lack of a control group. However, of the studies that have not had these limitations, the results are also promising. In general, studies show that intervention in the dental office can be effective and that group behavioral treatment may also improve cessation rates over minimal contact. On the other hand, pharmacological treatment, which has primarily focused on 2 mg nicotine gum, has not been found to be an effective treatment. Dentists are in an ideal position to advise and assist smokeless tobacco users to quit. The majority of smokeless tobacco users want advice and help from their dentists, and a significant number indicate that discussion of the negative oral effects from the use of smokeless tobacco has an impact on their desire to quit.

Safety of cotinine in humans: physiologic, subjective, and cognitive effects

Preliminary data suggest that cotinine, the major metabolite of nicotine, may be behaviorally active. Studies involving the administration of cotinine at doses that produce high blood concentrations (in excess of those produced by cigarette smoking) may be of interest. This inpatient, 10-day human study examined the safety and the effects from several high doses of oral cotinine fumarate (40, 80, or 160 mg) or placebo in abstinent cigarette smokers. All subjects smoked cigarettes ad lib during the first 2 days of the study, then were required to be abstinent beginning on the third day. All subjects were given placebo on this day to wash out nicotine before the administration of cotinine. Subjects were subsequently randomly assigned in a double-blind manner to cotinine or placebo for the next 3 days to determine the safety profile of cotinine. All subjects were given placebo on the final 3 days to examine cotinine withdrawal symptoms. The results showed no significant physiologic, subjective, or performance effects across the various doses of cotinine and placebo. Furthermore, no cotinine withdrawal effects were observed. This study demonstrates that short-term administration of cotinine to humans at levels as high as 10 times that attained from cigarette smoking is safe with no observable acute or withdrawal effects from cotinine in this setting.

Dissociation between subjective and behavioral responses after cocaine stimuli presentations

This study was designed to explore the relationship between craving and cocaine-seeking behavior with the use of both subjective and behavioral measures. Five males and five females who have used crack at least two times a week for 6 months, and who reported using 0.5 g of crack within 24 h on at least one occasion, participated in an inpatient study. Subjects underwent a total of four experimental sessions, during which they were exposed to either neutral (Neutral Stimuli Condition) or cocaine-related (Cocaine Stimuli Condition) external and internal stimuli. Subjects were exposed to each stimuli condition twice, on separate days, in randomized order. External stimuli comprised neutral or cocaine-related videotapes and paraphernalia, and the internal stimulus was either a 5-mg ('placebo') or 0.4 mg/kg delivery of cocaine. At baseline and after each stimulus exposure, subjects completed a composite cocaine craving questionnaire. Subjects next worked on concurrently-available fixed-ratio tasks either for tokens that could be exchanged for money ($2) or for tokens that were exchangeable for deliveries of cocaine (0.4 mg/kg). The results show that subjects reported significantly greater cocaine craving after exposure to cocaine-related vs. neutral stimuli, indicating that craving for cocaine can be successfully modeled in a laboratory setting. However, this change in subjective response did not predict drug-seeking behavior. The number of cocaine tokens earned following exposure to the cocaine-related vs neutral stimuli was similar. These results suggest that in a laboratory setting, craving may be unrelated to cocaine-seeking behavior in non-treatment-seeking cocaine users.

Society for Research on Nicotine and Tobacco

The proceedings of the second annual scientific conference of the Society for Research on Nicotine and Tobacco are summarized. The goal of the annual conference was to disseminate information about ongoing nicotine research from biological, behavioral and social perspectives. Data were presented describing our current understanding of the structure and function of neuronal nicotinic acetylcholine receptors, by which nicotine exerts most, if not all, of its effects in the brain. The conformational complexity of receptor subunits expressed in different brain areas contributes significantly to the complexity of responses observed to nicotinic agonists. Nicotine is being developed as a medication that might be used to maintain smoking cessation and to treat various medical diseases. The potential toxicity of nicotine, apart from cigarette smoking, is an important variable in assessing the benefits and risks of such therapeutic applications. The risks of nicotine-containing medications appear to be far less than those associated with tobacco use. Recent data indicate that cigarette smoking is increasing among young in the United States. Adolescent smokers are interested in quitting and make frequent quit attempts, but are usually not successful. Effective methods are needed to manage adolescent smokers before they become heavily addicted. Nicotine replacement as a pharmacological treatment for smoking cessation has made a significant contribution in improving quit rates. New medications have been developed that target specific populations of smokers.

Crack cocaine and cocaine hydrochloride. Are the differences myth or reality?

OBJECTIVE

To review and discuss the differences and similarities between the use of crack cocaine and cocaine hydrochloride; and to determine how these findings might affect policies on the imprisonment and treatment of cocaine users.

DATA SOURCES

English-language publications were identified through a computerized search (using MEDLINE) between 1976 and 1996 using the search terms "smoked cocaine," "crack cocaine," "freebase," and "cocaine-base." In addition, manual searches were conducted on references cited in original research articles, reviews, and an annotated bibliography, and on selected journals.

STUDY SELECTION

Only those articles that compared various routes of cocaine administration or types of cocaine (cocaine base or crack cocaine vs cocaine hydrochloride) were examined.

DATA EXTRACTION

Studies were reviewed to obtain information on the composition of the 2 forms of cocaine, and the prevalence, pharmacokinetics and pharmacodynamics, abuse liability, pattern of use, and consequences across the various routes of cocaine administration and forms of cocaine.

CONCLUSION

Cocaine hydrochloride is readily converted to base prior to use. The physiological and psychoactive effects of cocaine are similar regardless of whether it is in the form of cocaine hydrochloride or crack cocaine (cocaine base). However, evidence exists showing a greater abuse liability, greater propensity for dependence, and more severe consequences when cocaine is smoked (cocaine-base) or injected intravenously (cocaine hydrochloride) compared with intranasal use (cocaine hydrochloride). The crucial variables appear to be the immediacy, duration, and magnitude of cocaine's effect, as well as the frequency and amount of cocaine used rather than the form of the cocaine. Furthermore, cocaine hydrochloride used intranasally may be a gateway drug or behavior to using crack cocaine. Based on these findings, the federal sentencing guidelines allowing possession of 100 times more cocaine hydrochloride than crack cocaine to trigger mandatory minimum penalties is deemed excessive. Although crack cocaine has been linked with crime to a greater extent than cocaine hydrochloride, many of these crimes are associated with the addiction to cocaine. Therefore, those addicted individuals who are incarcerated for the sale or possession of cocaine are better served by treatment than prison.

Characterization of tobacco withdrawal symptoms: transdermal nicotine reduces hunger and weight gain

The accurate assessment of both tobacco withdrawal and the impact of the nicotine patch on withdrawal may be compromised by attrition of subjects, or by subjects smoking during withdrawal. To reduce these occurrences, 211 participants were provided with intensive cessation counseling while trying to quit smoking with either nicotine (21 mg) or placebo transdermal patches. Subject attrition was low, with 80.5% of participants continuing through the 5-week study period. Abstinence rates were also high over this period (75% and 61% in active and placebo groups, respectively). In this multisite, double-blind trial, withdrawal severity was assessed using a nine-item daily self-report questionnaire, and abstinence was confirmed via CO monitoring. Abrupt smoking cessation increased multiple tobacco withdrawal symptoms/signs including craving for cigarettes, irritability, anxiety, appetite, sleep disruption, difficulty concentrating, restlessness, depression, and impatience. Treatment with transdermal nicotine reduced craving for cigarettes, anxiety, irritability, and appetite, as well as weight gain (1.85 versus 2.88 kg mean gain over 4 weeks in active and placebo groups, respectively).

Gender differences in crack users who are research volunteers

This study compared gender differences in a non-treatment sample of crack cocaine users interested in participating in a research study on addiction. Data was collected from initial telephone screening interviews of women and men responding to cocaine research recruitment in a midwest urban environment over a two-year period. Female respondents (n = 88) were age- and race-matched with men interviewed over the same time period, for a total sample size of 176. Mean age of the female sample was 33 years and the majority were African-American. Basic demographics were similar for both genders. Respondents had first used cocaine at 24 years of age and currently smoked 2 g cocaine/day for 5 days/week, a rate higher than that found in many treatment samples. Women were found to have significantly higher rates of cigarette smoking, headaches and history of suicidal ideation, and significantly more women reported emergency room visits following crack use than did men. Equal numbers of men and women had been convicted of a crime (56%), with significantly fewer women reporting having committed a crime involving violence. Nearly all respondents (94%) reported that crack use had negative effects on their value systems, and significant numbers of both genders reported involvement with bartering crack and sex. Two-thirds of women able to become pregnant used no method of birth control and the use of barrier methods was infrequent. Forty-two percent admitted to using cocaine during pregnancy. These data indicate that while patterns of crack use per se do not differ between women and men in this sample, community outreach programs may benefit from focusing on other associated behaviors that do show differences between genders.

Effects of short-term use of nicotine gum in pregnant smokers

OBJECTIVES

To compare blood concentrations of nicotine and cotinine and maternal and fetal hemodynamic effects resulting from use of nicotine gum versus cigarette smoking in pregnant smokers.

METHODS

Pregnant women (24 to 36 weeks' gestation) who smoked chronically were randomly assigned with a 1:2 randomization scheme to either a group that smoked cigarettes (n = 10) or to a group that stopped smoking and chewed at least six pieces of nicotine gum (2 mg nicotine per piece) per day (n = 19). Blood nicotine and cotinine concentrations, maternal heart rate and blood pressure, uterine resistance index, and fetal heart rate and umbilical artery resistance index were obtained before and after one cigarette was smoked at baseline and after 5 continuous days of either chewing gum or smoking.

RESULTS

A significant reduction from baseline in nicotine (p < 0.0001) and cotinine (p < 0.0025) concentrations was observed in those who chewed nicotine gum compared with those who smoked cigarettes. No significant differences in the changes in maternal or fetal hemodynamic parameters from baseline to estimated time of peak nicotine exposure were observed between those who smoked cigarettes and those who chewed nicotine gum.

CONCLUSION

Short-term use of nicotine gum delivers less nicotine than usual cigarette smoking in pregnant women.

Smoked cocaine self-administration in females

Although approximately 32% of all smoked cocaine ("crack") users are women, most studies investigating cocaine use have recruited only male subjects. Therefore, this study examined the smoked cocaine self-administration patterns of female crack abusers. A work requirement, where up to five tokens were earned by subjects, was followed by the administration of a sample delivery of one of three dose sizes [5.0 mg (placebo), 0.2 mg/kg, 0.4 mg/kg] of cocaine. The three dose sizes of cocaine were administered in counterbalanced order across subjects, with each subject receiving one dose size within a session and all dose sizes across the three experimental sessions. A self-administration phase followed the sample delivery, during which a token could be exchanged every 30 min for monetary reimbursement or a delivery of cocaine in the same dose size as the sample delivery. The results show that females' patterns of behavioral and subjective responding to smoked cocaine exhibit clear dose-related effects, thus affirming this self-administration model as safe and appropriate for use with women.

Measuring dependence in smokeless tobacco users

Two scales based on the Fagerstrom Tolerance Questionnaire were developed to measure dependence in smokeless tobacco users. The total score for both scales correlated positively with saliva cotinine levels in subjects, and several individual items produced equally positive correlations. Regression analyses yielded two subsets of three items from each scale that predicted cotinine level. Reports of using smokeless tobacco within 30 min of waking served as a predictor in both models. For the purposes of measuring smokeless tobacco dependence, attention should be given to individual items correlated with saliva cotinine levels that could be used to determine the direction of cessation efforts. Future research should also develop additional items specific to the use of snuff or chewing tobacco and eliminate questions not contributing to the overall scale.

Pharmacodynamic effects of cotinine in abstinent cigarette smokers

The nicotine metabolite cotinine was administered to abstinent cigarette smokers to determine whether it has pharmacologic activity as assessed by various physiologic and subjective measurements. By means of a randomized, double-blind, placebo-controlled counterbalanced-order design, subjects received cotinine base (30 mg) intravenously after 48 hours of abstinence from cigarette smoking. Serum cotinine concentrations increased to levels commonly achieved during daily cigarette smoking, whereas no change in serum nicotine concentration was observed. Cotinine compared with placebo produced subjective differences in self-reported ratings of restlessness, anxiety and tension, insomnia, sedation, and pleasantness. Cotinine had minimal effects on cardiovascular measurements. These findings indicate that cotinine is behaviorally active in the setting of cigarette abstinence at blood concentrations similar to those commonly achieved through daily cigarette smoking.