Comparison of plasma nicotine concentrations after application of nicoderm (nicotine transdermal system) to different skin sites.

Drug absorption through the skin can vary according to the application site. The nicotine transdermal system, Nicoderm (Alza Corp., Palo Alto, CA) contains a rate-controlling membrane designed to regulate delivery of nicotine to the skin and thus limit variability in nicotine plasma levels. Plasma nicotine concentrations were compared after application of NTS 14 mg/day to three different skin sites (upper back, upper outer arm, upper chest) in a randomized, crossover study involving 12 healthy male smokers. Plasma nicotine profiles from all three sites were similar: nicotine concentrations increased rapidly within 2 to 4 hours, reached broad peaks of approximately 11 to 14 ng/mL, and then remained relatively constant between 8 and 24 hours after application. The mean nicotine maximum peak plasma concentration values for nicotine transdermal system application to the arm, back, and chest were equivalent (13.8, 14.6, and 13.2 ng/mL, respectively). The mean time to reach peak concentration (tmax) (3 to 6 hours), and area under the curve (168, 186, and 183 ng.h/mL) values for the arm, back, and chest, respectively, were not significantly different. Thus, bioequivalent plasma nicotine concentrations were achieved irrespective of the application site on the upper body.     

Bioavailability and absorption kinetics of nicotine following application of a transdermal system.

1. The absolute bioavailability and absorption kinetics of nicotine were investigated in 13 healthy adult male smokers following single and multiple applications of a nicotine transdermal system (NTS), designed to release nicotine at an approximate rate of 1.5 mg h-1 over 24 h. The absorption of nicotine from the single NTS application was calculated with reference to a simultaneous intravenous infusion (i.v.) of deuterium-labelled nicotine. 2. The mean input time (MIT) and mean absorption time (MAT) for nicotine following application of NTS for 24 h were 7.7 and 4.2 h, respectively. 3. Following NTS removal, the mean apparent nicotine elimination half-life was 2.8 h, compared with 2.0 h following i.v. nicotine, reflecting continued absorption of nicotine following NTS removal. 4. The mean amount of nicotine absorbed from the NTS after the 24 h application was 20.9 mg, which represents about 68% of the amount released from the system; the remaining 32% was lost from the system during daily activities. 5. The ratio of AUC values for the metabolite cotinine relative to nicotine was similar whether nicotine was administered transdermally or intravenously. 6. Following i.v. administration, the mean nicotine clearance was 72 l h-1 (coefficient of variation 29%). Since coefficients of variation in AUC values following NTS and i.v. treatments were similar, transdermal administration of nicotine was not associated with increased interindividual variability in plasma nicotine concentrations. 7. No significant changes were seen in the pharmacokinetics of nicotine between single and multiple applications of NTS. 8. As expected from the higher total plasma nicotine concentrations, the incidence of adverse effects was higher following simultaneous intravenous and transdermal administration of nicotine. The most frequently reported systemic side effects were nervousness and headache: mild itching was the most frequent topical effect.     

Pharmacokinetics of a rivastigmine transdermal patch formulation in healthy volunteers: relative effects of body site application

A patch formulation of rivastigmine, an inhibitor of acetylcholinesterase and butyrylcholinesterase, is under development. The current objective was to evaluate the pharmacokinetic profile and patch adhesiveness following application at the upper back, chest, abdomen, thigh, and upper arm. In a single-dose, open-label, crossover study with 40 (42.5% men) healthy subjects, a 10-cm(2) patch containing 18 mg rivastigmine was applied to each body site. Median t(max) was 16 hours for all sites except the thigh (22 hours). Exposure levels and C(max) were highest at the upper back, chest, and upper arm sites. Adhesiveness was greatest when applied to the thigh, followed by the abdomen, upper arm, chest, and upper back, although no statistically significant correlations with pharmacokinetic parameters were found, except at the chest (P=.02). Pharmacokinetic profiles and adhesiveness of the upper back, chest, and upper arm, coupled with low rates of erythema at these sites, suggest their suitability for clinical use.     

Comparison of nicotine pharmacokinetics in healthy Japanese male smokers following application of the transdermal nicotine patch and cigarette smoking

Transdermal nicotine patch (TNP) contains approximately 16.6 and 24.9 mg of nicotine per 20 and 30 cm2 (TNP-20 and TNP-30). The aims of the study are to investigate linearity of nicotine pharmacokinetics after single application of different strengths of TNP and to directly compare plasma nicotine concentrations with those during cigarette smoking. Twelve healthy Japanese male smokers were randomly allocated to 1 of 2 cohorts consisting of 6 subjects each. Cohort 1 subjects received 1 sheet of TNP-20 (TNP-20x1) in period 1, and 2 sheets of TNP-20 (TNP-20x2) in period 3. Cohort 2 subjects were received 1 sheet of TNP-30 (TNP-30x1) in period 2, and smoked a total of 12 cigarettes at 1 h intervals in period 4. Each TNP was applied to the upper arm for 16 h. After TNP-20x1 or TNP-20x2 treatment in cohort 1, the amount of nicotine delivered from TNP (Dose) was proportional to surface area of TNP. Cmax and AUC of nicotine increased with the surface area (Dose), and tmax, t(1/2), CL/F and percentage of dose excreted in urine were almost the same between both treatments. These suggest the linear pharmacokinetics of nicotine in proportion to the surface area and Dose following single application of TNP in identical subjects. In cohort 2, the plasma nicotine concentrations after TNP-30x1 treatment were approximately half those just before each smoking.     

Effects of smoking on the pharmacokinetics and pharmacodynamics of a nicotine patch

The effect of smoking on the pharmacokinetics and pharmacodynamics of a nicotine transdermal delivery system, administered as a single dose or multiple doses, was examined in smokers (n=12) and nonsmokers (n=12). The study was a two‐period, parallel trial. In the first period, a single dose of the Nicotinell TTS 20 patch was administered, followed by a 1‐week washout period. Then, in the second period, multiple doses of the Nicotinell TTS 20 patch were administered over 4 days. Regarding the pharmacokinetics of nicotine, the AUC_36h and AUC_τ of smokers were about 20% and 40% greater, respectively, than those of nonsmokers. Significant differences in heart rate were observed between smokers and nonsmokers at 10, 12, 16 and 24 h, and significant differences in systolic blood pressure were seen between smokers and nonsmokers at 12, 30 and 36 h in the single‐dose study. With multiple doses, significant differences in systolic and diastolic blood pressures were detected between smokers and nonsmokers only at 72.5 and 82 h. Here, it is demonstrated for the first time that the pharmacokinetic and hemodynamic effects of a nicotine patch are significantly different between smokers and nonsmokers. Copyright © 2008 John Wiley & Sons, Ltd.     

Effect of transdermal nicotine replacement on alcohol responses and alcohol self-administration

Rationale Nicotine replacement is commonly used to treat tobacco use in heavy-drinking smokers. However, few studies have examined the effect of nicotine replacement on subjective and physiological responses to alcohol and alcohol drinking behavior. Objective The primary aim of this within-subject, double-blind study was to examine whether transdermal nicotine replacement (0 mg vs 21 mg/day) altered response to a low-dose priming drink and subsequent ad libitum drinking behavior. Materials and methods Subjects (n = 19) were non-treatment-seeking, non-dependent heavy drinkers who were daily smokers. Six hours after transdermal patch application, subjective and physiological responses to a priming drink [designed to raise blood alcohol levels (BALs) to 0.03 g/dl] were assessed. This was followed by a 2-h self-administration period where subjects could choose to consume up to eight additional drinks (each designed to raise BALs by 0.015 g/dl) or to receive monetary reinforcement for drinks not consumed. Results We found that 6 h after patch application, tobacco craving associated with withdrawal relief was decreased, and systolic blood pressure and heart rate were increased in the active patch condition compared to the placebo patch condition. Subjective intoxication in response to the priming drink was attenuated in the active nicotine patch condition compared to 6 h of nicotine deprivation (i.e., placebo patch). During the self-administration period, subjects had longer latencies to start drinking and consequently appeared to consume fewer drinks when administered the active patch compared to the placebo patch. Conclusions In heavy drinkers, transdermal nicotine replacement compared to mild nicotine deprivation attenuated subjective and physiological alcohol responses and delayed the initiation of drinking.     

Effects of nicotine administered via a transdermal delivery system on vigilance: a repeated measure study

Fifteen 18- to 25-year-old male smokers were tested in a within-subjects design to determine the influence of a transdermal patch of 21 mg nicotine on vigilance. Subjects were tested on the RVIP test (Rapid Visual Information Processing test) 1.30, 3.00 and 6.30 h after patch application, to verify the involvement of the dose of nicotine on the performance. This study confirms and extends the increasing effects of nicotine on vigilance previously found with orally and transdermally given nicotine. Moreover, it showed that such performance was independent of the time of nicotine absorption (1.30, 3.00 and 6.30 h after patch application), which suggests that a relatively low dose of nicotine suffices to activate vigilance processing. Regarding motor performance, no convincing effect of nicotine was observed on reaction time. Received: 20 October 1997/Final version: 2 September 1998     

Transdermal delivery of nicotine in normal human volunteers: a single dose and multiple dose study

The absorption of nicotine delivered by a transdermal delivery system (TDS) was investigated in two separate studies, (A) a dose proportionality study and (B) a multiple dose study. In the dose range of 15-60 mg nicotine, the AUC and Cmax values were proportional to the dose. The levels achieved were in the same range as reported in smokers, following absorption from nicotine chewing gum. The TDS used in the present study produced sustained levels of nicotine for 24 h. No significant accumulation of nicotine was evident as a result of multiple dose administration using a 30-mg nicotine patch. Absorption of nicotine from the TDS was 80-90% and the rate of delivery was similar during both studies.     

Pharmacokinetics and bioavailability of nicotine in healthy volunteers following single and repeated administration of different doses of transdermal nicotine systems

Healthy nicotine-dependent smokers were applied different doses of transdermal nicotine systems (TNS) during single and repeated administrations. Plasma and urine nicotine and cotinine concentrations were determined by high performance liquid chromatography (HPLC). After single application of TNS, the maximal concentration (Cmax) and area under curve (AUC) of nicotine in plasma as well as the amount of nicotine excreted in urine were linearly related to the dose. The stable urinary cotinine excretion was not influenced by the amount of nicotine delivered by the TNS. The relevant 24 h plasma nicotine concentration reached after TNS application compares well with the plasma nicotine footpoints--not the peaks--observed in moderate to heavy cigarette smokers. A comparison between different nicotine doses from different TNS allowed to conclude to the functionality of the systems as regards pharmacokinetics and bioavailability. One or two hours after removal of the systems, there was a very slow decline of the nicotine concentrations. After repeated application of TNS, there was evidence for only a very limited nicotine accumulation in plasma (+14%) or in urine (+9%) over 10 days. The steady-state of nicotine was reached within 4 days. The continuous delivery of nicotine over 24 h resulted in an early morning plasma concentration which probably decreases or prevents the craving for the first cigarette.     

Transdermal nicotine for smoking cessation in postmenopausal women

This study examined the efficacy of transdermal nicotine in postmenopausal smokers, and whether a history of depression or hormone replacement therapy (HRT) moderated smoking cessation outcomes. Postmenopausal smokers (N=152) received intensive smoking cessation counseling and were randomly assigned to use either a 21-mg nicotine patch for 3 months, with a 1-month taper, or a placebo patch. The primary outcome was biochemically validated 7-day point prevalence smoking abstinence during treatment (i.e., 1, 2, 6, and 12 weeks after the quit date) and 1 year after study medication was discontinued. Subjects who received transdermal nicotine were significantly more likely than placebo-treated subjects to remain abstinent from smoking during treatment, but not at the 1-year follow-up. The majority of subjects (>50%) in both groups accurately identified their treatment assignment. History of depression was associated with a decreased likelihood to abstain from smoking throughout the study. HRT did not moderate smoking outcomes. These data indicate that transdermal nicotine may provide short-term benefits for smoking cessation in postmenopausal women. However, efforts are needed to improve long-term abstinence rates and smoking outcomes among women with a history of depression.     

Combination of behavioral smoking cessation with transdermal nicotine substitution

Effects of a transdermal nicotine substitution on psychological smoking cessation were investigated in a double-blind prospective study. 131 smokers were randomly assigned to three treatment conditions: All smokers underwent nine weeks of self-controlled smoking cessation. During six weeks one group was additionally treated with nicotine patches continuously releasing nicotine through the skin into the blood circuit. The second group received placebo patches; while the third group was treated with behavioral training alone. Treatment effects were measured by daily cigarette consumption. Nicotine-treated subjects reached significantly higher abstinence rates during and at the end of treatment than both placebo- and control-subjects: 69% in the nicotine condition, 51.2% and 44.4% under placebo and control conditions respectively. Effects are influenced by initial cigarette consumption, with the light smokers benefitting most from the nicotine patch. Self-assessments suggest an aversive effect of transdermal nicotine on cigarette taste. Our results, although not yet verified by long-term observations, demonstrate that transdermal nicotine substitution significantly enhances the effectiveness of behavioral smoking cessation methods.     

Long-term nicotine substitution after application of a 16-hour nicotine patch in smoking cessation

Summary The purpose of the study was to examine long-term nicotine substitution and its variability during use of a nicotine patch. In two smoking cessation studies a 16-h nicotine patch, releasing 15 mg nicotine, was applied daily for 16 h over 12 weeks, to 167 smokers. Salivary cotinine was highly correlated with plasma cotinine (r = 0.93), and the concentration of cotinine in a single sample in the afternoon was well correlated with the AUC_cotinine over 24 h (r = 0.94). The salivary cotinine concentration after 1 week in 60 abstainers was 183 ng · ml^–. After 3, 6 and 12 weeks the cotinine concentrations were 86%, 79% and 59% of the 1-week value. The degree of nicotine compensation attained by the patch after 1 week was 52% (SD 24%) in subjects who succeeded in stopping smoking for at least 3 weeks. A quarter of the subjects achieved a compensation of less than 35% of their usual nicotine intake. Nicotine substitution with this 16-h nicotine patch was stable and the risk of overcompensation was small in this group of smokers.     

Pharmacokinetics of a contraceptive patch (Evra/Ortho Evra) containing norelgestromin and ethinyloestradiol at four application sites

AIMS: To determine the pharmacokinetic profile of norelgestromin (NGMN) and ethinyloestradiol (EE) following application of the contraceptive patch, Evra/Ortho Evra, at each of four anatomic sites (abdomen, buttock, arm, and torso). METHODS: Thirty-seven healthy, nonpregnant women aged 20-45 years participated in this open-label, four-period crossover study. Subjects were randomized to one of four treatment (site of application) sequences. Each patch was worn for 7 days, with a 1 month washout between treatments. Blood samples were collected before and at various times up to 240 h after application of each patch. Serum samples were assayed for NGMN and EE by validated methods. RESULTS: The serum concentration reference ranges for NGMN and EE are 0.6-1.2 ng ml-1 and 25-75 pg ml-1, respectively, based on studies of the mean Cave of oral norgestimate 250 microg and EE 35 microg. For all application sites, mean concentrations of NGMN and EE remained within these ranges during the 7 day wear period. Absorption of NGMN and EE during patch application on the buttock, arm, and torso was equivalent. Absorption of NGMN and EE during patch application on the abdomen was approximately 20% less than observed for the other three sites, although mean serum concentrations were still within reference ranges. A previous study demonstrated therapeutic equivalence of patches worn on the abdomen vs other sites. CONCLUSIONS: Serum concentrations of NGMN and EE from the contraceptive patch remain within the reference ranges throughout the 7 day wear period, regardless of the site of application (abdomen, buttock, arm, or torso).     

High dose transdermal nicotine therapy for heavy smokers: safety,tolerability and measurement of nicotine and cotinine levels

Transdermal nicotine has been shown to relieve nicotine withdrawal and to double smoking cessation rates compared to placebo in clinical trials. A 21 or 22 mg/day dose provides a steady state serum nicotine that is less than obtained from smoking. Limited information is available about higher nicotine patch doses. To define better the optimal dosing of nicotine patch therapy, we undertook an open-label study to determine the safety and tolerability of 44 mg/day dose for smoking cessation in subjects smoking 20 cigarettes per day. Forty smokers received 44 mg/day of transdermal nicotine for 4 weeks followed by 4 weeks of 22 mg/day. Of the 40 subjects enrolled, 38 (95%) completed the 4 weeks of 44 mg patch therapy and 36 (90%) completed the entire 8 weeks of patch therapy. Non-smokers at week 4 had a mean serum nicotine level of 23.4±11.7 ng/ml and cotinine of 152.2±87.3 ng/ml. Percent replacement was calculated by dividing the steady state level at week 4 by the baseline level while the subjects were smoking their usual number of cigarettes. Percent nicotine replacement for non-smokers at week 4 (while on 44 mg nicotine patch) averaged 158%±108.4, and for cotinine was 112.0±73.8. For nicotine, 33% of non-smokers at week 4 had 100% nicotine replacement and for cotinine 63% 100% replacement. Biochemically confirmed point prevalence smoking cessation rates were 65% and 55% at weeks 4 and 8 of patch therapy, respectively, and self-reported smoking cessation at 3 months was 50%. The most common effect was skin irritation at the patch site. A single subject was admitted for myocardial infarction following step-down from 44 to 22 mg of replacement nicotine. The subject was not smoking and the adverse event was deemed to be not related to the patch therapy. Sleep complaints were reported in 33% of subjects during the 44 mg phase. Other complaints were infrequent. We conclude that 44 mg per 24-h nicotine patch therapy in heavy smokers is safe, tolerable, and without significant adverse events.     

Nicotine metabolic rate predicts successful smoking cessation with transdermal nicotine: A validation study

Transdermal nicotine is widely used for smoking cessation, but only ~ 20% of smokers quit successfully with this medication. Interindividual variability in nicotine metabolism rate may influence treatment response. This study sought to validate, and extend in a larger sample, our previous finding that the ratio of plasma nicotine metabolites 3′-hydroxycotinine (3-HC)/cotinine, a measure of nicotine metabolism rate, predicts response to nicotine patch. A sample of 568 smokers was enrolled in a study that provided counseling and 8-weeks of 21 mg nicotine patch. Pretreatment 3-HC/cotinine ratio was examined as a predictor of 7-day point prevalence abstinence, verified with breath carbon monoxide (CO), 8 weeks after the quit date. Controlling for sex, race, age, and nicotine dependence, smokers in the upper 3 quartiles of 3-HC/cotinine ratio (faster metabolizers) were ~ 50% less likely to be abstinent vs. smokers in the first quartile (slow metabolizers; 28% vs. 42%; OR = .54 [95% CI:.36-.82], p = .003). Among abstainers, plasma nicotine levels (assessed 1 week after treatment began) decreased linearly across the 3-HC/cotinine ratio (β = − 3.38, t[355] = − 3.09, p < .05). These data support the value of the 3-HC/cotinine ratio as a biomarker to predict success with transdermal nicotine for smoking cessation.     

Double-blind placebo controlled trial of dextrose tablets and nicotine patch in smoking cessation

 In a placebo-controlled double-blind trial 308 smokers were individually randomly allocated to one of four groups: 1) 3 g dextrose tablets and 15 mg nicotine transdermal patch; 2) dextrose and placebo patch; 3) placebo tablets and nicotine patch; 4) placebo tablets and placebo patch. Patients were scheduled to attend weekly smokers clinic sessions starting 1 week before the quit date and continue for 4 weeks after that date. The primary outcome variable was biochemically verified abstinence at the final session, four weeks after the scheduled quit date. The proportion of smokers abstinent in the four groups was as follows: 49% – dextrose plus active patch; 44% – dextrose plus placebo patch; 36% – placebo tablet plus active patch; 30% – placebo tablet plus placebo patch. The difference between the dextrose and placebo tablets (13%) was statistically significant (P < 0.01, one-tailed); the difference between the active and placebo patches (6%) was not. There was no significant difference between the effect of the dextrose when accompanied by active versus placebo patches. There was no significant effect of dextrose on weight. The results suggest that dextrose supplementation to the diet may be a cheap and simple aid to giving up smoking. Further research is now needed to establish its long-term efficacy. Received: 7 July 1997/Final version: 26 September 1997     

Extended duration therapy with transdermal nicotine may attenuate weight gain following smoking cessation

Aim

People who quit smoking often gain 11–12 lb, on average, which can frequently lead to a relapse to smoking. This study evaluated whether extended vs. standard duration treatment with nicotine patch helps those able to quit smoking to reduce cessation-induced weight gain and explored nicotine patch adherence as a mediator of treatment effects.

Design and setting

We examined data from a completed randomized placebo-controlled clinical trial of extended (24 weeks) vs. standard (8 weeks plus 16 weeks of placebo) transdermal nicotine patch therapy. Changes in measured weight over 24 weeks were compared across the two treatment arms, controlling for gender, baseline smoking rate, and previous weight. Adherence to patch use was assessed using self-report of daily use over 24 weeks.

Participants

139 clinical trial participants who were confirmed to be abstinent at weeks 8 and 24.

Findings

Compared to participants who received 8 weeks of nicotine patch therapy, participants who received 24 weeks of treatment showed significantly less weight gain from pre-treatment to week 24 (β = −4.76, 95% CI: −7.68 to −1.84, p = .002) and significantly less weight gain from week 8 to week 24 (β = −2.31, 95% CI: −4.39 to −0.23, p = .03). Extended treatment increased patch adherence which, in turn, reduced weight gain; patch adherence accounted for 20% of the effect of treatment arm on weight gain.

Conclusion

Compared to 8 weeks of transdermal nicotine therapy, 24 weeks of patch treatment may help to reduce the weight gain that is typical among smokers who are able to achieve abstinence from tobacco use. Extended treatment increased nicotine patch adherence which, in turn, reduced weight gain.     

Sensitivity and tolerance to nicotine in smokers and nonsmokers

We studied the responses of smokers and life-long non-smokers to transdermal nicotine patches over 24 h in three groups of subjects: non-smokers on a 15 mg patch (n=8), non-smokers on a 30 mg patch (n=8) and smokers on a 30 mg patch (n=8). Unexpectedly, the non-smokers appeared to absorb nicotine more rapidly. The increase in blood nicotine concentrations of non-smokers over the first 2 h of patch use was double that of the smokers, with mean increases of 4.5 (SD=3.7), 10.9 (SD=4.2) and 4.1 (SD=2.7) ng/ml in the three groups, respectively (P<0.005). The smokers had no pleasant or unpleasant effects from the 30 mg patch ( C_max 13.9 ng/ml, SD=4.9; T_max 8.75 h) but all eight non-smokers experienced mild nausea and lightheadedness (P<0.01) within the first hour, and seven dropped out (P<0.01) at 3–8 h due mainly to severe nausea, vomiting or headache ( C_max 18.4 ng/ml, SD=4.9; T_max 5.25 h). Only one non-smoker dropped out on the 15 mg patch, but five had transient nausea in the first hour ( C_max 7.9 ng/ml, SD=3.0; T_max 8.0). Our study provides evidence of chronic pharmacodynamic nicotine tolerance in smokers, but does not address whether this is acquired or innate. The higher rate of transdermal nicotine absorption in non-smokers is unexplained and requires replication.     

基于内标微透析技术同步分析尼古丁透皮贴剂在血液与皮肤的药动学

目的：利用内标微透析采样技术,同步研究尼古丁透皮贴剂的血液和皮肤局部药动学特征,获得其较全面的体内药动学规律。方法：以健康SD大鼠为实验动物,将尼古丁透皮贴剂经皮给药,磷酸可待因作为微透析采样的内标物,采集不同时间点血液和皮肤微透析样品,用高效液相色谱法（HPLC）进行测定,利用DAS 2.1药动学软件计算相关药动学参数。结果：尼古丁在血液和皮肤的平均滞留时间（MRT_0-∞）分别为（16 986.00±486.00）min和（1 597.00±851.00）min,药时曲线下面积（AUC_0-∞）分别为（19 235.42±1 801.92）mg·mL^-1·min和（56 328.82±24 900.42）mg·mL^-1·min,达峰浓度（C_max）分别为（2.00±0.50）mg·L^-1和（32.00±5.00）mg·L^-1,达峰时间（t_max）分别为（325±200）min和（570±106）min。尼古丁在血液与皮肤的药动学参数相比,AUC_0-∞、C_max、t_max在皮肤中较大,MRT_0-∞在血液中较大。结论：尼古丁透皮贴剂经皮给药后,在血液与皮肤的药动学规律存在明显的差异与联系,药动学参数证明尼古丁通过透皮渗透在皮肤中以相对较高的浓度蓄积,能达到快速、有效的吸收,进入血液后血药浓度相对较低且维持稳定,发挥显著长效作用。     

Physical exercise increases plasma concentrations of nicotine during treatment with a nicotine patch.

The effect of physical exercise on plasma nicotine concentrations was studied in eight healthy subjects treated with a nicotine patch releasing 14 mg 24 h-1. After 11 h of patch application, plasma nicotine concentrations were measured before and after 20 min of moderate bicycle exercise, or 20 min of rest. Mean plasma nicotine concentration increased from 9.8 to 11.0 ng ml-1 (P = 0.015) during physical exercise, and fell non-significantly from 10.5 to 10.2 ng ml-1 during rest. The increase in plasma nicotine concentration during exercise is similar to that observed for transdermal nitroglycerin, and may be related to an exercise-induced increase in blood flow in the patch area.