Modafinil and nicotine interactions in abstinent smokers

Pharmacokinetic and pharmacodynamic of the cognitive enhancer modafinil: Relevant clinical and forensic aspects

Modafinil is a nonamphetamine nootropic drug with an increasingly therapeutic interest due to its different sites of action and behavioral effects in comparison to cocaine or amphetamine. A review of modafinil (and of its prodrug adrafinil and its R-enantiomer armodafinil) chemical, pharmacokinetic, pharmacodynamic, toxicological, clinical and forensic aspects was performed, aiming to better understand possible health problems associated to its unconscious and unruled use. Modafinil is a racemate metabolized mainly in the liver into its inactive acid and sulfone metabolites, which undergo primarily renal excretion. Although not fully clarified, major effects seem to be associated to inhibition of dopamine reuptake and modulation of several other neurochemical pathways, namely noradrenergic, serotoninergic, orexinergic, histaminergic, glutamatergic and GABAergic. Due its wake-promoting effects, modafinil is used for the treatment of daily sleepiness associated to narcolepsy, obstructive sleep apnea and shift work sleep disorder. Its psychotropic and cognitive effects are also attractive in several other pathologies and conditions that affect sleep structure, induce fatigue and lethargy, and impair cognitive abilities. Additionally, in health subjects, including students, modafinil is being used off-label to overcome sleepiness, increase concentration and improve cognitive potential. The most common adverse effects associated to modafinil intake are headache, insomnia, anxiety, diarrhea, dry mouth and raise in blood pressure and heart rate. Infrequently, severe dermatologic effects in children, including maculopapular and morbilliform rash, erythema multiforme and Stevens-Johnson Syndrome have been reported. Intoxication and dependence associated to modafinil are uncommon. Further research on effects and health implications of modafinil and its analogs is steel needed to create evidence-based policies.

The Role of Cognitive Control in the Self-Regulation and Reinforcement of Smoking Behavior

Cognitive control (CC)-the ability to regulate attention and memory-plays an important role in a variety of health behaviors, including smoking behavior. In this theoretical review of the literature, we propose a CC and smoking behavior framework that includes (1) the positive influence of CC on the self-regulation of smoking, (2) nicotine-induced improvements in CC that may indirectly reinforce smoking (including withdrawal reversal effects), and (3) the long-term effects of smoking on the brain that may result in reduced CC. Integration of these literatures suggests that CC contributes to both self-regulation (ie, brake pedal) and nicotine-related reinforcement (ie, gas pedal) amid the catastrophic effects of long-term smoking, which may reduce self-regulatory control over smoking while also enhancing indirect reinforcement. Supportive evidence and limitations of this approach will be presented, as well as ideas for future research directions that may fully examine this multifaceted modeling of CC in relation to smoking behavior.

IMPLICATIONS

There is substantial evidence that CC contributes to self-regulation (ie, brake pedal) and reinforcement (ie, gas pedal) of smoking behavior as well as evidence that long-term smoking may cause reduced CC. The proposed model delineates how these opposing influences of CC may mask the unique contribution of self-regulation and reinforcement in maintaining smoking behavior. Targeting CC for treating nicotine dependence will require more nuanced approaches that consider the independent and combined effects of self-regulation and reinforcement to improve smoking cessation success rates.

New Pharmacological Agents to Aid Smoking Cessation and Tobacco Harm Reduction: What Has Been Investigated, and What Is in the Pipeline?

A wide range of support is available to help smokers to quit and to aid attempts at harm reduction, including three first-line smoking cessation medications: nicotine replacement therapy, varenicline and bupropion. Despite the efficacy of these, there is a continual need to diversify the range of medications so that the needs of tobacco users are met. This paper compares the first-line smoking cessation medications with (1) two variants of these existing products: new galenic formulations of varenicline and novel nicotine delivery devices; and (2) 24 alternative products: cytisine (novel outside Central and Eastern Europe), nortriptyline, other tricyclic antidepressants, electronic cigarettes, clonidine (an anxiolytic), other anxiolytics (e.g. buspirone), selective serotonin reuptake inhibitors, supplements (e.g. St John's wort), silver acetate, Nicobrevin, modafinil, venlafaxine, monoamine oxidase inhibitors (MAOIs), opioid antagonists, nicotinic acetylcholine receptor (nAChR) antagonists, glucose tablets, selective cannabinoid type 1 receptor antagonists, nicotine vaccines, drugs that affect gamma-aminobutyric acid (GABA) transmission, drugs that affect N-methyl-D-aspartate (NMDA) receptors, dopamine agonists (e.g. levodopa), pioglitazone (Actos; OMS405), noradrenaline reuptake inhibitors and the weight management drug lorcaserin. Six 'ESCUSE' criteria-relative efficacy, relative safety, relative cost, relative use (overall impact of effective medication use), relative scope (ability to serve new groups of patients) and relative ease of use-are used. Many of these products are in the early stages of clinical trials; however, cytisine looks most promising in having established efficacy and safety with low cost. Electronic cigarettes have become very popular, appear to be efficacious and are safer than smoking, but issues of continued dependence and possible harms need to be considered.

Medications between psychiatric and addictive disorders

INTRODUCTION

Many epidemiological studies have revealed a frequent co-occurrence of psychiatric and substance use disorders. The term used in the literature to refer to this co-occurrence is dual diagnosis. The high prevalence of dual diagnosis has led physicians to observe the effects of medication prescribed to treat psychiatric disorders on the co-occurring substance use disorder and vice versa. The concept of medications between psychiatric and addictive disorders stems from these clinical observations, alongside which, however, it has developed from the observation that both psychiatric and substance use disorders share common neurobiological pathways and trigger common cognitive disorders. This has led researchers to develop medications on the basis of neurobiological and cognitive rationales.

MATERIAL AND METHOD

In our article, we review peculiar medications based on neurobiological and cognitive rationales and that have an impact in both psychiatric and addictive disorders.

RESULTS

We highlight how interesting these new prescriptions are for clinical observation and for the treatment of patients suffering from dual diagnosis.

CONCLUSION

We then go on to discuss the interest in them from the perspective of clinical practice and clinical research, in that the development of medications to treat dual diagnosis helps to further our knowledge of both psychiatric and substance use disorders.

R-modafinil attenuates nicotine-taking and nicotine-seeking behavior in alcohol-preferring rats

(±)-Modafinil (MOD) is used clinically for the treatment of sleep disorders and has been investigated as a potential medication for the treatment of psychostimulant addiction. However, the therapeutic efficacy of (±)-MOD for addiction is inconclusive. Herein we used animal models of self-administration and in vivo microdialysis to study the pharmacological actions of R-modafinil (R-MOD) and S-modafinil (S-MOD) on nicotine-taking and nicotine-seeking behavior, and mechanisms underlying such actions. We found that R-MOD is more potent and effective than S-MOD in attenuating nicotine self-administration in Long-Evans rats. As Long-Evans rats did not show a robust reinstatement response to nicotine, we used alcohol-preferring rats (P-rats) that display much higher reinstatement responses to nicotine than Long-Evans rats. We found that R-MOD significantly inhibited intravenous nicotine self-administration, nicotine-induced reinstatement, and nicotine-associated cue-induced drug-seeking behavior in P-rats. R-MOD alone neither sustained self-administration in P-rats previously self-administering nicotine nor reinstated extinguished nicotine-seeking behavior. The in vivo brain microdialysis assays demonstrated that R-MOD alone produced a slow-onset moderate increase in extracellular DA. Pretreatment with R-MOD dose-dependently blocked nicotine-induced dopamine (DA) release in the nucleus accumbens (NAc) in both naive and nicotine self-administrating rats, suggesting a DA-dependent mechanism underlying mitigation of nicotine's effects. In conclusion, the present findings support further investigation of R-MOD for treatment of nicotine dependence in humans.

Cardiovascular stimulant actions of bupropion in comparison to cocaine in the rat

Stimulants are banned in competition by the World Anti-Doping Agency, except for a small number of therapeutic agents subject to monitoring, including bupropion. We have examined the potency of bupropion in comparison with two agents banned in competition, adrafinil and modafinil, and with cocaine and desipramine as blockers of the noradrenaline re-uptake transporter in peripheral tissues of the rat. For studies in vivo, the pressor response to noradrenaline in the anaesthetized rat was studied. Cocaine, desipramine and bupropion at doses of 0.1, 0.3 and 1mg/kg, respectively, significantly increased the pressor response to noradrenaline. Overall, cocaine and desipramine were approximately 2-5 times more potent than bupropion in vivo in the rat. Adrafinil and modafinil (both 3mg/kg) did not significantly affect the pressor response. Bupropion was chosen for further study. In 1Hz paced rat right ventricular strips, bupropion (30μM) significantly increased the potency of noradrenaline at increasing the force of contraction. In rat vas deferens, bupropion and cocaine produced concentration-dependent increases in the contractile response to nerve stimulation, and cocaine was 11 times more potent than bupropion. Since bupropion is used clinically in doses of up to 300mg, it is likely that bupropion has actions at the noradrenaline transporter, and thus cardiovascular stimulant actions, in clinical doses. This may explain findings of increased exercise performance with bupropion.

An efficient early phase 2 procedure to screen medications for efficacy in smoking cessation

RATIONALE

Initial screening of new medications for potential efficacy (i.e., Food and Drug Administration (FDA) early phase 2), such as in aiding smoking cessation, should be efficient in identifying which drugs do, or do not, warrant more extensive (and expensive) clinical testing.

OBJECTIVES

This focused review outlines our research on development, evaluation, and validation of an efficient crossover procedure for sensitivity in detecting medication efficacy for smoking cessation. First-line FDA-approved medications of nicotine patch, varenicline, and bupropion were tested as model drugs, in three separate placebo-controlled studies. We also tested specificity of our procedure in identifying a drug that lacks efficacy, using modafinil.

RESULTS

This crossover procedure showed sensitivity (increased days of abstinence) during week-long "practice" quit attempts with each of the active cessation medications (positive controls) versus placebo, but not with modafinil (negative control) versus placebo, as hypothesized. Sensitivity to medication efficacy signal was observed only in smokers high in intrinsic quit motivation (i.e., already preparing to quit soon) and not smokers low in intrinsic quit motivation, even if monetarily reinforced for abstinence (i.e., given extrinsic motivation).

CONCLUSIONS

A crossover procedure requiring less time and fewer subjects than formal trials may provide an efficient strategy for a go/no-go decision whether to advance to subsequent phase 2 randomized clinical trials with a novel drug. Future research is needed to replicate our results and evaluate this procedure with novel compounds, identify factors that may limit its utility, and evaluate its applicability to testing efficacy of compounds for treating other forms of addiction.

Sensitivity and specificity of a procedure for early human screening of novel smoking cessation medications

BACKGROUND AND AIM

It is important to find economical methods in early Phase 2 studies to screen drugs potentially useful to aid smoking cessation. A method has been developed that detects efficacy of varenicline and nicotine patch. This study aimed to evaluate whether the method would detect the efficacy of bupropion and identify correctly the lack of efficacy of modafinil.

DESIGN

Using a within-subject double cross-over design, smokers attempted to quit during each treatment, with bupropion (150 mg b.i.d.), modafinil [100 mg twice daily (b.i.d.)] or placebo (double-blind, counterbalanced order). In each of three medication periods, all smoked with no drug on week 1 (baseline or washout), began dose run-up on week 2, and tried to quit every day during week 3.

SETTING

A university research center in the United States.

PARTICIPANTS

Forty-five adult smokers high in quit interest.

MEASUREMENTS

Abstinence was verified daily each quit week by self-report of no smoking over the prior 24 hours and carbon monoxide (CO) < 5 parts per million.

FINDINGS

Compared with placebo, bupropion did (F(1,44)  = 6.98, P = 0.01), but modafinil did not (F(1,44)  = 0.29, P = 0.60), increase the number of abstinent days. Also, bupropion (versus placebo) significantly increased the number of those able to maintain continuous abstinence on all 5 days throughout the quit week (11 versus four), Z = 2.11, P < 0.05, while modafinil did not (six).

CONCLUSIONS

Assessing days abstinent during 1 week of use of medication versus placebo in a cross-over design could be a useful early Phase 2 study design for discriminating between medications useful versus not useful in aiding smoking cessation.

Effect of modafinil on impulsivity and relapse in alcohol dependent patients: a randomized, placebo-controlled trial

Poor impulse control plays an important role in the development, course and relapse of substance use disorders. Therefore, improving impulse control may represent a promising approach in the treatment of alcohol dependence. This study aimed to test the effect of modafinil on impulse control and alcohol use in alcohol dependent patients (ADP) in a randomized, double-blind, placebo-controlled trial. Eighty-three abstinent ADP were randomized to 10 weeks modafinil (300 mg/d) or placebo. Alcohol use was quantified using the timeline follow-back method and was assessed until 6 months after treatment discontinuation. Impulsivity was assessed using self-report questionnaires (Barratt Impulsiveness Scale; State Impulsivity questionnaire) and neurocognitive tasks (Stop Signal Task; Delay Discounting Task) administered before, during and after treatment. Modafinil significantly improved self-report measures of state impulsivity, but had no effect on percentage of abstinent days or percentage of heavy drinking days, nor on the behavioral measures of impulsivity. However, subgroup analysis revealed that modafinil prolonged the time to relapse (p=.022) and tended to increase the percentage of abstinent days (p=.066) in ADP with poor response inhibition at baseline, whereas modafinil increased the percentage of heavy drinking days (p=.003) and reduced the percentage of abstinent days (p=.002) in patients with better baseline response inhibition. Overall results do not favor the use of modafinil in order to reduce relapse or relapse severity in ADP, and caution is required in prescribing modafinil to a non-selected sample of ADP. Further research on the effect of modafinil in ADP with poor baseline response inhibition is warranted.

Galantamine attenuates some of the subjective effects of intravenous nicotine and improves performance on a Go No-Go task in abstinent cigarette smokers: a preliminary report

RATIONALE

Galantamine (GAL), a reversible and competitive inhibitor of acetylcholinesterase, is used clinically in the treatment of Alzheimer's dementia. Some preclinical and clinical studies support the potential efficacy of cholinesterase inhibitors for smoking cessation, although their effects on the behavioral and physiological responses to nicotine have not been examined. The goal of this study was to characterize GAL's actions on multiple outcomes, including withdrawal severity and cognitive performance, as well as subjective and physiological responses to nicotine administered intravenously.

METHODS

A total of 12 smokers participated in a double-blind, placebo-controlled, crossover study. Smokers had two 4-day treatment periods, assigned in random sequence, to GAL (8 mg/day) or placebo treatment. On day 4 of each treatment phase, smokers had an experimental session in which they received an intravenous (IV) dose of saline or 1 mg/70 kg nicotine, 1 h apart, in a random order.

RESULTS

GAL attenuated the self-reported rating of "craving for cigarettes" and prevented decrements in performance in a Go/No-Go task. In response to IV nicotine, GAL treatment attenuated the self-report ratings of "like the drug effects," "good drug effects," "bad drug effects," and "stimulated."

CONCLUSIONS

These findings support the potential utility of GAL as a treatment for smoking cessation.

The safety of modafinil in combination with oral ∆9-tetrahydrocannabinol in humans

Marijuana (cannabis) is the most widely used illicit substance globally, and cannabis use is associated with a range of adverse consequences. Currently, no medications have been proven to be effective for the treatment of cannabis addiction. The goals of this study were to examine the safety and efficacy of a potential treatment medication, modafinil, in combination with oral ∆9-tetrahydrocannabinol (THC). Twelve male and female occasional cannabis users participated in an outpatient double-blind, placebo-controlled, crossover study. Across four sessions, participants were randomly assigned to a sequence of four oral treatments: (1) 400 mg modafinil+placebo, (2) 15 mg THC+placebo, (3) 400 mg modafinil+15 mg THC, or (4) placebo+placebo. Outcome measures included heart rate, blood pressure, performance on the Rapid Visual Information Processing (RVIP), and the Hopkins Verbal Learning Test (HVLT), and subjective measures. Oral THC increased heart rate, and produced increased subjective ratings of feeling "high" and "sedated," as well as increased ratings of euphoria. Modafinil alone increased the Profiles of Mood States (POMS) subscales of vigor and tension. These findings support the safety of modafinil in combination with THC. The effects of modafinil in combination with a range of doses of THC need to be determined in future studies.

Reinforcing effects of nicotine and non-nicotine components of cigarette smoke

RATIONALE

Nicotine and non-nicotine components of cigarette smoke contribute to its reinforcing effects; however, the specific role of each component in maintaining behavior has not yet been elucidated.

OBJECTIVES

To assess the reinforcing effects of nicotine and non-nicotine components of cigarette smoke by presenting a concurrent choice paradigm in which participants had access to intravenous (IV) nicotine infusions vs. saline (placebo) infusions and puffs from denicotinized ("denic") cigarettes vs. air (sham puffs). We also measured the effects on self-administration of prior satiation with each component.

METHODS

Sixteen smokers participated in seven sessions: 1) a baseline smoking assessment, used to tailor the nicotine dose per infusion; 2) two sessions for training discrimination of IV nicotine vs. saline infusions and denic smoke vs. sham puffs; and 3) four sessions assessing choice behavior after different satiation conditions.

RESULTS

Denic smoke was self-administered more than any other alternative, including IV nicotine. IV nicotine, however, was preferred over IV saline and sham puffs. Preference for denic smoke vs. IV nicotine was inversely correlated with subjective ratings of "comfort" associated with nicotine. Smoke satiation reduced the number of denic puffs taken during choice periods, while prior nicotine administration did not affect puffing behavior. Smoking withdrawal symptoms were alleviated both by nicotine administration and by denic smoke.

CONCLUSIONS

In established smokers, non-nicotine aspects of cigarette smoking have potent reinforcing effects. While current smoking cessation pharmacotherapies primarily address the nicotine component of cigarette addiction, future cessation strategies should also be designed to target non-nicotine factors.

Varenicline attenuates some of the subjective and physiological effects of intravenous nicotine in humans

RATIONALE

Varenicline, a partial nicotinic acetylcholine receptor (nAChR) agonist, is approved for smoking cessation. A few preclinical studies examined the pharmacological effects of varenicline, alone or in combination with nicotine. How varenicline affects the pharmacological effects of pure nicotine has not been examined in humans. The goal of this study was to characterize varenicline's actions on nicotine's dose-dependent effects in abstinent smokers.

METHODS

Six male and six female smokers participated in a double-blind, placebo-controlled, crossover study. Smokers had two 4-day treatment periods, assigned in random sequence, to varenicline (1 mg/day) or placebo treatment. On day 4 of each treatment phase, smokers had an experimental session, where they received three escalating doses of intravenous (IV) nicotine (0.1, 0.4, and 0.7 mg/70 kg), in 30-min intervals. Varenicline's effects were assessed through subjective, physiological, and cognitive performance outcomes to nicotine administered via IV route.

RESULTS

In response to IV nicotine, varenicline treatment attenuated the rating of drug strength, high, head rush, and stimulated. Varenicline also attenuated nicotine-induced increases in heart rate. Varenicline had mixed effects on cognitive performance. Smokers under varenicline treatment, compared with placebo, reported enhanced positive mood measured with the Positive and Negative Affect Schedule.

CONCLUSIONS

These findings provide new insights into the mechanisms of action of varenicline in smoking cessation.

Modafinil and memory: effects of modafinil on Morris water maze learning and Pavlovian fear conditioning

Modafinil has been shown to promote wakefulness and some studies suggest the drug can improve cognitive function. Because of many similarities, the mechanism of action may be comparable to classical psychostimulants, although the exact mechanisms of modafinil's actions in wakefulness and cognitive enhancement are unknown. The current study aims to further examine the effects of modafinil as a cognitive enhancer on hippocampus-dependent memory in mice. A high dose of modafinil (75 mg/kg ip) given before training improved acquisition on a Morris water maze. When given only before testing, modafinil did not affect water maze performance. We also examined modafinil (0.075 to 75 mg/kg) on Pavlovian fear conditioning. A low dose of pretraining modafinil (0.75 mg/kg) enhanced memory of contextual fear conditioning (tested off-drug 1 week later) whereas a high dose (75 mg/kg) disrupted memory. Pretraining modafinil did not affect cued conditioning at any dose tested, and immediate posttraining modafinil had no effect on either cued or contextual fear. These results suggest that modafinil's effects of memory are more selective than amphetamine or cocaine and specific to hippocampus-dependent memory.

A placebo-controlled trial of modafinil for nicotine dependence

BACKGROUND

Nicotine deprivation symptoms, including fatigue and attentional deficits, predict relapse following smoking cessation. Modafinil (Provigil), a wakefulness medication shown to have efficacy for the treatment of cocaine addiction, was tested as a novel therapy for nicotine dependence in a double-blind placebo-controlled trial.

METHODS

One hundred and fifty-seven treatment-seeking smokers received brief smoking cessation counseling and were randomized to: (1) 8 weeks of modafinil (200mg/day), or (2) 8 weeks of placebo. The primary outcome was biochemically verified 7-day point prevalence abstinence at the end of treatment (EOT). Secondary outcomes included cigarette smoking rate and post-quit nicotine deprivation symptoms (e.g., negative affect, withdrawal).

RESULTS

In this interim study analysis, EOT quit rates did not differ between treatment arms (42% for placebo vs. 34% for modafinil; OR=0.67 [0.34-1.31], p=0.24). Further, from the target quit date to EOT, the daily smoking rate was 44% higher among non-abstainers in the modafinil arm, compared to non-abstainers in the placebo arm (IRR=1.44, CI95=1.09-1.89, p<0.01). Modafinil-treated participants also reported greater increases in negative affect and withdrawal symptoms, vs. participants randomized to placebo (ps<0.05).

CONCLUSIONS

These data do not support the use of modafinil for the treatment of nicotine dependence and, as a consequence, this trial was discontinued. Cigarette smoking should be considered when modafinil is prescribed, particularly among those with psychiatric conditions that have high comorbidity with nicotine dependence.