Impact of formulation on the abuse liability, safety and regulation of medications: the expert panel report

Psychedelic drug abuse potential assessment research for new drug applications and Controlled Substances Act scheduling

New medicines containing classic hallucinogenic and entactogenic psychedelic substance are under development for various psychiatric and neurological disorders. Many of these, including psilocybin, lysergic acid diethylamide (LSD), and 3,4-methylenedioxymethamphetamine (MDMA) are Schedule I controlled substances of the United States Controlled Substances Act (US CSA), and similarly controlled globally. The implications of the CSA for research and medicines development, the path to approval of medicines, and their subsequent removal from Schedule I in the US are discussed. This entire process occurs within the framework of the CSA in the US and its counterparts internationally in accordance with international drug control treaties. Abuse potential related research in the US informs the eight factors of the CSA which provide the basis for rescheduling actions that must occur upon approval of a drug that contains a Schedule I substance. Abuse-related research also informs drug product labeling and the risk evaluation and mitigation strategies (REMS) will likely be required for approved medicines. Human abuse potential studies typically employed in CNS drug development may be problematic for substances with strong hallucinogenic effects such as psilocybin, and alternative strategies are discussed. Implications for research, medicinal development, and controlled substance scheduling are presented in the context of the US CSA and FDA requirements with implications for global regulation. We also discuss how abuse-related research can contribute to understanding mechanisms of action and therapeutic effects as well as the totality of the effects of the drugs on the brain, behavior, mood, and the constructs of spirituality and consciousness.

Abuse Deterrent Formulations in Constraining the Abuse Potential of Prescription Medicines: A Myth or Truth

BACKGROUND

Diverse pain killers used for the management of varied categories of pain are being misused in order to have extreme pleasant effect by a large number of populations. To overcome the misuse of prescription drugs, regulatory bodies have given stress on development of abuse resistance.

METHODS

We studied numerous literatures: (1) Research and review papers including the guidelines for pain management, abuse, and abuse deterrence; (2) Description and categorization of pain along with the management approaches; (3) advantages and disadvantages of the abuse deterrent formulations were described.

RESULTS

Abuse deterrent formulations are the contemporary remedial treatment for pain with reduced prospects of being abused. But these comprise the huge expense in contrast to the generic drugs as well as the non-deterrent branded equivalents.

CONCLUSION

Many challenges are faced throughout the development of abuse deterrent formulations. These formulations displayed substantial drop in abuse incidences but it may lead to other modes of abuse which may prove more harmful for the users.

Human Abuse Potential of the New Opioid Analgesic Molecule NKTR-181 Compared with Oxycodone

Objective

Evaluate the human abuse potential, pharmacokinetics, pharmacodynamics, and safety of NKTR-181, a novel mu-opioid agonist molecule, relative to oxycodone.

Design

This randomized, single-center, double-blind, active- and placebo-controlled five-period crossover study enrolled healthy, adult, non–physically dependent recreational opioid users.

Setting

Inpatient clinical research site.

Subjects

Forty-two randomized subjects (73.8% male, 81% white, mean age = 25 years).

Methods

The primary objective was to evaluate single orally administered 100, 200, and 400 mg NKTR-181 doses in solution compared with 40 mg oxycodone and placebo solutions using the Drug Liking visual analog scale. Secondary measures included the Drug Effects Questionnaire, Addiction Research Center Inventory/Morphine Benzedrine Group Subscale, Price Value Assessment Questionnaire, Global Assessment of Overall Drug Liking, and Take Drug Again Assessment. Central nervous system mu-opioid effects were assessed using pupillometry. The study included qualifying and treatment phases. Subjects received each of the five treatments using a crossover design.

Results

NKTR-181 at all dose levels had significantly lower Drug Liking E_max than oxycodone (P < 0.0001). Drug Liking scores for oxycodone increased rapidly within 15 minutes and peaked at approximately one hour postdose, whereas Drug Liking (and most secondary abuse potential measures) for all doses of NKTR-181 were comparable with placebo for at least the first hour. Only the 400 mg Drug Liking scores were minimally differentiated vs placebo from one and a half to four hours, but remained significantly lower than oxycodone (P < 0.003). NKTR-181 treatment-related adverse effects were mild and occurred at a lower rate compared with oxycodone.

Conclusions

NKTR-181 demonstrated delayed onset of CNS effects and significantly lower abuse potential scores compared with oxycodone in recreational opioid users.

Pharmacodynamic and pharmacokinetic assessment of electronic cigarettes, combustible cigarettes, and nicotine gum: implications for abuse liability

RATIONALE

Electronic cigarettes (ECs) are becoming popular alternatives for smokers, but there has been limited study of their abuse liability.

OBJECTIVES

The objective of this study was to evaluate the abuse liability of three Vuse Solo ECs, ranging from 14 to 36 mg in nicotine content, relative to high- and low-abuse liability comparator products (usual brand combustible cigarettes and nicotine gum, respectively) in a group of 45 EC-naïve smokers.

METHODS

Enrolled subjects' ratings of subjective effects and nicotine uptake over 6 h were used to measure abuse liability and pharmacokinetics following in-clinic use of each EC.

RESULTS

Use of Vuse Solo resulted in subjective measures and nicotine uptake that were between those of combustible cigarettes and nicotine gum, although generally closer to nicotine gum. Compared to combustible cigarettes, use of Vuse Solo resulted in significantly lower scores in measures of product liking, positive effects, and intent to use again. These pharmacodynamic findings were consistent with the pharmacokinetic data, showing that cigarettes produced substantially faster and higher levels of nicotine uptake as compared to Vuse Solo and nicotine gum. Vuse Solo resulted in more rapid initial uptake of nicotine compared to nicotine gum, but peak concentration and long-term extent of uptake were not different or were lower with Vuse.

CONCLUSIONS

Collectively, these findings suggest that Vuse Solo likely has an abuse liability that is somewhat greater than nicotine gum but lower than cigarettes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02269514.

Methods and predictors of tampering with a tamper-resistant controlled-release oxycodone formulation

BACKGROUND

In April 2014, a tamper-resistant controlled-release oxycodone formulation was introduced into the Australian market. This study aimed to identify the level and methods of tampering with reformulated oxycodone, demographic and clinical characteristics of those who reported tampering with reformulated oxycodone, and perceived attractiveness of original and reformulated oxycodone for misuse (via tampering).

METHODS

A prospective cohort of 522 people who regularly tampered with pharmaceutical opioids and had tampered with the original oxycodone product in their lifetime completed two interviews before (January-March 2014: Wave 1) and after (May-August 2014: Wave 2) introduction of reformulated oxycodone.

RESULTS

Four-fifths (81%) had tampered with the original oxycodone formulation in the month prior to Wave 1; use and attempted tampering with reformulated oxycodone amongst the sample was comparatively low at Wave 2 (29% and 19%, respectively). Reformulated oxycodone was primarily swallowed (15%), with low levels of recent successful injection (6%), chewing (2%), drinking/dissolving (1%), and smoking (<1%). Participants who tampered with original and reformulated oxycodone were socio-demographically and clinically similar to those who had only tampered with the original formulation, except the former were more likely to report prescribed oxycodone use and stealing pharmaceutical opioid, and less likely to report moderate/severe anxiety. There was significant diversity in the methods for tampering, with attempts predominantly prompted by self-experimentation (rather than informed by word-of-mouth or the internet). Participants rated reformulated oxycodone as more difficult to prepare and inject and less pleasant to use compared to the original formulation.

CONCLUSION

Current findings suggest that the introduction of the tamper-resistant product has been successful at reducing, although not necessarily eliminating, tampering with the controlled-release oxycodone formulation, with lower attractiveness for misuse. Appropriate, effective treatment options must be available with increasing availability of abuse-deterrent products, given the reduction of oxycodone tampering and use amongst a group with high rates of pharmaceutical opioid dependence.

Evaluating the potential impact of a reformulated version of oxycodone upon tampering, non-adherence and diversion of opioids: the National Opioid Medications Abuse Deterrence (NOMAD) study protocol

AIMS

A new oxycodone formulation (Reformulated OxyContin® was released in Australia, early 2014. It was developed as a tamper-resistant ('abuse-deterrent') formulation of the drug. We summarize methods used in the National Opioid Medication Abuse Deterrence (NOMAD) study, which will examine: (i) whether there is a reduction in extra-medical use (including via tampering) of OxyContin® following the introduction of Reformulated OxyContin®; (ii) potential changes in extra-medical use of non-abuse-deterrent forms of oxycodone, other pharmaceutical opioids and illicit drugs; (iii) whether methods of tampering with Reformulated OxyContin® become widespread over time; (iv) Reformulated OxyContin®'s attractiveness on the illicit market; and (v) sales, prescriptions and harms related to OxyContin® and other drugs.

METHODS

There are three major components. First, analyses of existing routine data sources such as: pharmaceutical sales; prescribing data; data on drug overdose deaths; and survey data on drug use in the general population and among people who inject drugs; secondly, specific data on OxyContin® collected through the Illicit Drug Reporting System; and thirdly, a prospective cohort of n = 606 people who regularly misuse or tamper with pharmaceutical opioids was formed prior to the introduction of Reformulated OxyContin®, followed-up twice post-release to examine potential changes after Reformulated OxyContin®'s introduction.

DISCUSSION

The study's strengths lie in varied data collections; interrupted time-series analysis; and prospective cohort. To our knowledge, this is one of the most comprehensive and transparently conducted studies conducted to date of the potential impact of an opioid medication upon use, tampering and diversion. Results have the potential to inform policymakers, clinicians, consumers and researchers alike.

Current topics in opioid therapy for pain management: addressing the problem of abuse

Opioids are an established therapy for cancer pain and have become an accepted therapy for chronic noncancer pain. However, increased prescribing of opioids in recent years has been accompanied by an increase in prescription opioid abuse. All opioids have inherent potential for abuse, but gaps in healthcare provider understanding of or adherence to best prescribing practices may facilitate the misdirection of opioids for abuse. To address these concerns, the US Food and Drug Administration has required pharmaceutical manufacturers to develop Risk Evaluation and Mitigation Strategies (REMS) for prescribers of extended-release/long-acting (ER/LA) opioids and has encouraged research to develop opioid formulations that are less easily abused or less attractive for abuse. The ER/LA opioid REMS require a partnership between the pharmaceutical industry, regulators, and healthcare providers to develop educational materials for physicians and patients that are not promotional. This article addresses challenges associated with improving the quality of pain care through support of prescriber education, developing formulations that combine efficacy with tamper-resistant properties, and encouraging collaborative efforts by regulatory bodies, legislators, healthcare providers, and patient advocacy groups to achieve these ends.

An iterative model for in vitro laboratory assessment of tamper deterrent formulations

BACKGROUND

In an effort to address the continuing problem of prescription opioid abuse, manufacturers are incorporating new technologies into formulations that are designed to deter product tampering and misuse. Standards for laboratory assessment of tamper deterrent properties of new formulations have not previously been developed.

METHODS

Experimental designs were developed for the in vitro laboratory assessment of the tamper deterrent properties of reformulated oxycodone. Given that an exhaustive study of all potential tampering methods was impractical; this model was developed to evaluate the product in an incremental fashion with iterative changes that were amenable to objective and replicable laboratory testing.

RESULTS

A description of the model is provided along with pertinent examples involving assessment of reformulated oxycodone with comparisons to the original formulation. Physical and chemical procedures were developed that relate to "real-world" scenarios that may be applied to opioid formulations. Test results were interpreted in relation to the relative ease or difficulty of the manipulation as compared to control materials and the amount and purity of active drug that could be accessed. Results from some of the tests were designed to be useful in predicting whether specific tampering methods would facilitate or deter drug administration by different routes of administration.

CONCLUSIONS

This model, developed to assess the tamper deterrent properties of reformulated oxycodone, should have application in the assessment of other drug formulations designed to exhibit tamper deterrence properties.

Update on tamper-resistant drug formulations

An expert panel convened in 2005 by the College on Problems of Drug Dependence (CPDD) to consider strategies to reduce the risk of prescription medication abuse concluded that drug formulation plays a significant role in determining risk of abuse. Efforts on the part of the pharmaceutical industry to develop drugs that deter abuse have focused primarily on opioid formulations resistant to common forms of tampering, most notably crushing or dissolving the tablet to accelerate release. Several opioid formulations developed to be tamper resistant have been approved, but the US Food and Drug Administration has not approved explicit label claims of abuse deterrence and has stated that any such claim will require substantial postmarketing data. Drug development efforts in this area raise questions about the relative impact of abuse-deterrent formulations, not only on individuals who might abuse a medication, but also on patients who are compliant with therapy. This review discusses progress since the 2005 CPDD meeting with an emphasis on opioids. Articles cited in the review were identified via a PubMed search covering the period between January 1, 2000, and October 5, 2011. Scientific work presented by the authors and their colleagues at meetings held through May 2012 also was included. Published literature suggests that development of abuse-deterrent products will require broad public health support and continued encouragement from regulatory authorities so that such products will become the expected standard of care for certain drug classes.

Adolescent use of prescription drugs to get high in Canada

OBJECTIVE

To present epidemiologic information on adolescent use of prescription drugs to get high, and not for medical purposes, in Canada.

METHODS

Data were obtained from 44 344 adolescents in grades 7 to 12 living across Canada's 10 provinces who completed the Youth Smoking Survey in 2008/2009.

RESULTS

Nationally, 5.9% of adolescents in grades 7 to 12 reported the use of prescription drugs to get high in the past 12 months in 2008/2009. Females were more likely to report use of pain relievers, sedatives, or tranquilizers to get high, while males were more likely to report the use of prescription stimulants for this purpose. The use of prescription drugs to get high was elevated among older youth, those living in British Columbia, and those who identified as First Nations, Métis, or Inuit. School connectedness was associated with a reduction in this form of prescription drug misuse for all adolescents; however, this protective effect was particularly strong for Aboriginal youth, and may be an important preventative factor for this population.

CONCLUSIONS

Use of prescription drugs to get high was prevalent among adolescents in Canada in 2008/2009. Findings highlight the need for clinicians to include questions about prescription drugs when screening adolescents for substance abuse in Canada. Findings also highlight the need for evidence-informed strategies to reduce prescription drug misuse among Aboriginal youth living outside First Nations communities in Canada. The results of this study suggest school connectedness may be a particularly important target for these interventions.

Postmarketing surveillance for "modified-risk" tobacco products

INTRODUCTION

The U.S. Food and Drug Administration (FDA) acquired authority to regulate tobacco products in 2009. This authority will provide a structured process for manufacturers to introduce products that may have "modified-risk" for morbidity or mortality relative to traditional tobacco products, with postmarketing surveillance and studies a condition of marketing.

METHOD

A narrative review approach was taken. The author searched and integrated publicly accessible literature on tobacco product surveillance as well as drug and medical device postmarket activities currently performed by FDA.

RESULTS

FDA relies on active and passive methods for postmarket surveillance and can require specific studies and risk evaluation and mitigation strategies for certain products, including those with abuse liability. Past efforts at examining the individual and population effects of reduced harm tobacco products provide an example of integrating different data streams.

DISCUSSION

Postmarket surveillance can be viewed in terms of the Agent-Host-Vector-Environment model, and concepts from diffusion of innovations are relevant to understanding factors associated with the adoption of new products by the population. Given that active and passive surveillance approaches have different strengths and weaknesses, multiple approaches may be necessary to evaluate population-level effects. Assuring that required studies are properly conducted and reported and that data indicating significant public health harms are quickly recognized will be important going forward.

CONCLUSIONS

The advent of broad regulatory authority over tobacco provides opportunities for policy evaluation research. The research community can provide FDA with the independent science it needs to evaluate the public health impact of novel tobacco products.

When drugs in the same controlled substance schedule differ in real-world abuse, should they be differentiated in labeling?

The prescription drugs regulated in the most restrictive controlled substance schedule for those with an approved therapeutic use vary widely in their real world risk of abuse and harm. Opioid analgesics have the highest rates of abuse, overdose death, drug abuse treatment needs and societal costs in comparison to other Schedule II drugs. Stimulants for attention-deficit/hyperactivity disorders (ADHD) account for substantially lower rates of abuse, harm, and public health impact. The scheduling of drugs is determined by the World Health Organization, the United States Food and Drug Administration, and other regulatory agencies, through a quasi-public process that relies heavily on pre-marketing studies that are conducted in highly controlled clinical settings. We propose that it is increasingly in the interest of science-based regulation and public health to recognize and communicate differences among drugs based on their real-world abuse and public health harm using surveillance data. Appropriate differentiation through labeling of drugs that will likely remain in the same schedule could provide powerful incentives for drug development and research, would aid prescriber/patient decision making by informing them of real differences across drugs within a schedule, and may also contribute to public health efforts to reduce drug abuse. There are risks of course, that include inadvertent perceptions that drugs labeled to be lower in risk are not taken as seriously as others in the same category. Challenges such as these, however, can be overcome and should not serve as barriers to objective communications regarding a drug's actual risks.

Post-marketing surveillance of buprenorphine-naloxone in Australia: diversion, injection and adherence with supervised dosing

BACKGROUND

These studies compared the diversion and injection of buprenorphine-naloxone (BNX), buprenorphine (BPN) and methadone (MET) in Australia.

METHODS

Surveys were conducted with regular injecting drug users (IDUs) (2004-2009, N=881-943), opioid substitution treatment (OST) clients (2008, N=440) and authorised OST prescribers (2007, N=291). Key outcome measures include the unsanctioned removal of supervised doses, diversion, injection, motivations, drug liking and street price. Levels of injection among IDUs were adjusted for background availability of medications. Doses not taken as directed by OST clients were adjusted by total number of daily doses dispensed.

RESULTS

Among regular IDUs, levels of injection were lower for BNX relative to BPN, but comparable to those for MET, adjusting for background availability. Among OST clients, fewer BNX clients (13%) reported recently injecting their medication, than BPN (28%) and MET clients (23%). Fewer MET clients (10%) reported removal of supervised doses, than BPN (35%) and BNX clients (22%). There were no differences in prevalence of recent diversion (28% of all OST clients). Adjusting for the total doses dispensed, more BPN was injected (10%), removed (12%) and diverted (5%), than MET (5%, <1% and 2% respectively) and BNX (5%, 9% and <1% respectively). In 2009, the median street price of BNX was equivalent to that for BPN.

CONCLUSIONS

BNX was less commonly and less frequently injected than BPN, but both sublingual medications were diverted more than liquid MET.

[Post-marketing surveillance systems for psychoactive prescription drug abuse]

Drugs affecting the central nervous system form a unique group of products for surveillance because they could be misused, abused or diverted. Considering the characteristics of this behaviour that is often concealed, specific post-marketing surveillance systems have been developed to monitor abuse of prescription drugs in some countries. The purpose of this review is to list and to describe post-marketing surveillance systems, according their methodology, in France and in foreign countries. These programs are based on adverse effect notifications, medical or legal consequences of abuse, general or specific population-based survey, professional networks or medication databases. Some programs use simultaneously several information sources. In conclusion, the multifaceted nature, the diversity and the inventiveness of post-marketing surveillance systems reflects the complexity of the abuse issue.

Conference on abuse liability and appeal of tobacco products: conclusions and recommendations

The rate of initiation and progression to dependence and premature mortality are higher for tobacco products than for any other dependence producing substance. This is not explained simply by the addictiveness ("abuse liability") or by enticing product designs ("product appeal") alone, but rather by both of these factors in combination with marketing and social influences that also influence "product appeal". A working meeting of leading experts in abuse liability (AL) and product appeal was convened to examine how these disciplines could be more effectively applied to the evaluation of tobacco products for the purposes of regulation that would include setting standards for designs and contents intended to reduce the risk of initiation and dependence. It was concluded that abuse liability assessment (ALA) is a validated approach to testing pharmaceutical products but has not been extensively applied to tobacco products: such application has demonstrated feasibility, but special challenges include the diverse range of products, product complexity, and the absence of satisfactory placebo products. Consumer testing for product appeal is widely used by consumer product marketers as well as by researchers in their efforts to understand consumer product preferences and use but has not been extensively applied to tobacco products except by the tobacco industry. Recommendations for testing, methods development, and research were developed. A major recommendation was that tobacco products should be tested for AL and product appeal, and the results integrated and evaluated so as to more accurately predict risk of initiation, dependence, and persistence of use.

Prevalence and correlates of 12-month prescription drug misuse in Alberta

OBJECTIVE

We examined the prevalence and correlates of prescription drug misuse (PDM) in a population-based sample of adults from Alberta.

METHODS

Data were collected from 3511 adults in Alberta aged 18 years and older in 2002 using a computer-aided telephone survey; the survey response rate was 57.4%.

RESULTS

The prevalence of 12-month PDM in Alberta was 8.2% in 2002. Opiates were the most frequently misused drug class, followed by sedatives, stimulants, and tranquilizers. Current disability was particularly associated with PDM. Odds of PDM were also elevated among adult students and adults with a high school diploma relative to adults with a post-secondary degree. Past-year problem gambling, illicit drug use, and alcohol use and dependence were each associated with PDM, while past-year binge drinking and daily smoking were not.

CONCLUSIONS

Findings suggest PDM was an important public health concern in Alberta in 2002. Estimates suggest prescription use and misuse have increased substantially in Canada since that time. There is an urgent need for an ongoing assessment of this evolving problem so that effective prevention and therapeutic strategies can be developed.

Risk management and post-marketing surveillance of CNS drugs

Drugs affecting the central nervous system span a broad range of chemical entities, dosage forms, indications, and risks. Unintended consequences include potential abuse and overdose in non-patient drug abusers, deliberate tampering of drug dosage forms, and criminal behavior associated with diversion. Regulators must consider diverse factors to find the appropriate conditions of approval to minimize unintended consequences while enabling a level of access desired by health care providers and patients. This commentary appears as part of a special issue of Drug and Alcohol Dependence that focuses on risk management and post-marketing surveillance and addresses key issues that pose real-world challenges to pharmaceutical sponsors and regulators in particular. For example, in the U.S., Controlled Substances Act drug scheduling can be considered a risk management strategy but its legal authorities and administrative processes are independent from those of risk management (including Risk Evaluation and Mitigation Strategies or REMS); better harmonization of these approaches is vital from drug development and regulatory perspectives. Risk management would ideally be implemented on a strong science foundation demonstrating that the tools employed to mitigate risks and ensure safe use are effective. In reality, research and evaluation of tools in this area is in its infancy and will necessarily be an evolutionary process; furthermore, there is little precedent for linking interventions and program evolution to unintended consequences such as regional outbreaks of abuse and diversion. How such issues are resolved has the potential to stimulate or stifle innovations in drug development and advance or imperil health care.

Abuse liability assessment of tobacco products including potential reduced exposure products

The harm produced by tobacco products is a result of frequent use of a highly toxic product. Reducing the adverse public health impact of tobacco products might be most effectively achieved by reducing the likelihood of their use and the toxicity of the products. Products that retain some characteristics of cigarettes but have been altered with the intention of reducing toxicity have been referred to as modified risk tobacco products or potential reduced exposure products (MRTP/PREP). Evaluation of their content, emission, and toxicity is discussed in other articles in this special issue. Here, we discuss the methodology that has been used to examine the likelihood of abuse or addiction. Abuse liability assessment (ALA) methodology has been used by the Food and Drug Administration (FDA) and other drug regulatory agencies world-wide for decades to assess the risks posed by a wide variety of pharmacologically active substances. ALA is routinely required among other evaluations of safety during the pre-market assessment of new drugs, and is continually adapted to meet the challenges posed by new drug classes and drug formulations. In the 2009 law giving FDA regulation over tobacco products, FDA is now required to evaluate new tobacco products including MRTP/PREPs to determine their risk for abuse and toxicity at the population level. This article describes the traditional tools and methods of ALA that can be used to evaluate new tobacco and nicotine products including MRTP/PREPs. Such ALA data could contribute to the scientific foundation on which future public policy decisions are based.

Monitoring risk: post marketing surveillance and signal detection

The primary goal of postmarketing surveillance is to provide information for risk assessment of a drug. Drugs affecting the central nervous system form a unique group of products for surveillance because they are often misused, abused, and diverted. These medications include opioid analgesics, stimulants, sedative-hypnotics, muscle relaxants, anticonvulsants and other drug classes. Their adverse events are difficult to monitor because the perpetrator often attempts to conceal the misuse, abuse and diversion of the product. A postmarketing surveillance system for prescription drugs of abuse in the U.S. should include product specific information that is accurate, immediately available, geographically specific and includes all areas of the country. Most producers of branded opioid analgesic products have created systems that measure abuse from multiple vantage points: criminal justice, treatment professionals, susceptible patient populations and acute health events. In the past, the U.S. government has not established similar requirements for the same products produced by generic manufacturers. However, the Food and Drug Administration Amendments Act of 2007 includes generic opioid analgesic products by requiring that all products containing potent opioid drugs perform rigorous surveillance and risk management. While general risk management guidance has been developed by FDA, more specific analyses and guidance are needed to improve surveillance methodology for drugs which are misused, abused, diverted.

Risk management and post-marketing surveillance for the abuse of medications acting on the central nervous system: expert panel report

The abuse and diversion of medications is a significant public health problem. This paper is part of a supplemental issue of Drug and Alcohol Dependence focused on the development of risk management plans and post-marketing surveillance related to minimizing this problem. The issue is based on a conference that was held in October 2008. An Expert Panel was formed to provide a summary of the conclusions and recommendations that emerged from the meeting involving drug abuse experts, regulators and other government agencies, pharmaceutical companies and professional and other non-governmental organizations. This paper provides a written report of this Expert Panel. Eleven conclusions and 11 recommendations emerged concerning the state of the art of this field of research, the regulatory and public health implications and recommendations for future directions. It is concluded that special surveillance tools are needed to detect the emergence of medication abuse in a timely manner and that risk management tools can be implemented to increase the benefit to risk ratio. The scientific basis for both the surveillance and risk management tools is in its infancy, yet progress needs to be made. It is also important that the unintended consequences of increased regulation and the imposition of risk management plans be minimized.

Principles of laboratory assessment of drug abuse liability and implications for clinical development

Abuse liability testing plays an important role in informing drug development, regulatory processes, and clinical practice. This paper describes the current "gold standard" methodologies that are used for laboratory assessments of abuse liability in non-human and human subjects. Particular emphasis is given to procedures such as non-human drug discrimination, self-administration, and physical dependence testing, and human dose-effect abuse liability studies that are commonly used in regulatory submissions to governmental agencies. The potential benefits and risks associated with the inclusion of measures of abuse liability in industry-sponsored clinical trials is discussed. Lastly, it is noted that many factors contribute to patterns of drug abuse and dependence outside of the laboratory setting and positive or negative signals in abuse liability studies do not always translate to high or low levels of actual abuse or dependence. Well-designed patient and physician education, pharmacovigilance, and postmarketing surveillance can reduce the diversion and misuse of drugs with abuse liability and can effectively foster the protection and promotion of public health.

Drug-abuse deterrent formulations

Prescription drug abuse is a large and growing problem. In the decade between 1992 and 2002, prescriptions for controlled substances increased roughly three times faster than prescriptions for noncontrolled substances and 12 times faster than the general population. With drug/formulation tampering now a prevalent problem, regulators and manufacturers have turned to the manufacturing process for ways to decrease the likelihood that a specific formulation is abuse-ready. Abuse-deterrent formulations are one aspect of a comprehensive approach to prescription drug risk management. Several approaches seem most likely to deter misuse and abuse: adding agonists or excipients that foil tampering efforts, using physical barriers, and designing prodrugs.

Abuse liability of intra-nasal midazolam in inhaled-cocaine abusers

Intra-nasally instilled benzodiazepines have been proposed for acute anxiety episodes. However, routes with faster absorption may increase abuse liability. This study compared abuse liability of intra-nasal midazolam between subjects with a history of intra-nasal drug abuse and non-psychiatric subjects on a single-blind randomized controlled trial. Thirty-one inhaled-cocaine abusers and 34 normal volunteers received either 1 mg intra-nasal midazolam or active placebo. Visual analogue scales assessing desire to repeat the experience (ER) and Experience Liking (EL) assessed abuse liability. Profile analysis for repeated measures showed a significant effect of time over ER (F([5,57])=3.311, p=0.011) and EL (F([5,57])=3.947, p=0.004), diagnostic group (cocaine abusers scoring higher on both - F([5,57])=5.229, p=0.026; F([5,57])=4.946, p=0.030), regardless of the administered substance. It is concluded that the intra-nasal route does not seem to pose risks for non-psychiatric individuals, but it may represent a risk in itself for subjects with a history of drug abuse through this path.

The role of human drug self-administration procedures in the development of medications

The purpose of this review is to illustrate the utility and value of employing human self-administration procedures in medication development, including abuse liability assessments of novel medications and evaluation of potential pharmacotherapies for substance use disorders. Traditionally, human abuse liability testing has relied primarily on subjective reports describing drug action by use of questionnaires; similarly, drug interactions between putative treatment agents and the drugs of abuse have relied on these measures. Subjective reports are highly valued because they provide qualitative and quantitative information about the characteristics of central and peripheral pharmacodynamic effects as well as safety and tolerability. However, self-administration procedures directly examine the behavior of interest-that is, drug taking. The present paper (1) reviews the most commonly used human self-administration procedures, (2) discusses the concordance of subjective reports and self-administration within the context of medications development for substance use disorders, focusing primarily on illustrative examples from development efforts with opioid and cocaine dependence, and (3) explores the utility of applying self-administration procedures to assess the abuse liability of novel compounds, including "abuse-deterrent" formulations (ADFs). The review will focus on opioid and cocaine dependence because a rich database from both clinical laboratory and clinical trial research exists for these two drug classes. The data reviewed suggest that drug-induced changes in self-administration and subjective effects are not always concordant. Therefore, assessment of self-administration in combination with subjective effects provides a more comprehensive picture that may have improved predictive validity for translating to the clinical setting.

The nonmedical use of prescription ADHD medications: results from a national Internet panel

BACKGROUND

Emerging evidence suggests that nonmedical use (NMU) of prescription attention deficit/hyperactivity disorder (ADHD) medications is rising, but many previous investigations have used clinical or regionally based samples or limited their investigations to stimulants rather than to medications specifically used to treat ADHD. Using an Internet-based epidemiological survey, this paper advances understanding of the prevalence and correlates of NMU of medications used to treat ADHD, sources of diverted medications, motivations for use, and consumption patterns.

METHODS

The study used a self-administered Internet survey of civilian, noninstitutionalized adults (N = 4,297) aged 18 to 49 in the United States. National-level estimates were created using propensity scoring methods and weighting procedures using data from three nationally representative probability surveys: a random-digit dialed telephone survey, the current U.S. Census, and the National Survey on Drug Use and Health (NSDUH).

RESULTS

Past-year prevalence of NMU of ADHD medications was approximately 2%, with 4.3% reported among those aged 18 to 25 and 1.3% among those aged 26 to 49. Most respondents reporting NMU used on multiple occasions. Receipt of medications for ADHD was a significant correlate of past-year NMU, though most nonmedical users never had a prescription. Among persons who had never been prescribed medication to treat ADHD, friends or family members were the most common source. Productivity was the most frequently endorsed reason for NMU. Alcohol was the substance most commonly used in combination with ADHD drugs.

CONCLUSION

Because most prescription ADHD medications currently are highly regulated, policy options for supply-side reduction of nonmedical use may include identifying those medications with lower abuse liability for inclusion on insurance formularies. Patient and physician education programs also may be useful tools to heighten awareness of intentional and unintentional diversion of ADHD medications for nonmedical purposes.

Incidence and antecedents of nonmedical prescription opioid use in four US communities. The Coronary Artery Risk Development in Young Adults (CARDIA) prospective cohort study

BACKGROUND

Nonmedical use of prescription opioids has emerged as a major public health problem during the last decade, but direct measures of incidence and predisposing factors are lacking.

METHODS

We prospectively measured incidence and antecedents of nonmedical prescription opioid use in The Coronary Artery Risk Development in Young Adults study among 28-40-year-old African- and European-American men and women with no prior history of nonmedical opioid use.

RESULTS

Among 3163 participants, 23 reported new nonmedical prescription opioid use in 2000-2001 (5-year incidence 0.7%; 95%CI: 0.4-1.0%). All 23 had previously reported marijuana use (p<0.001). Five-year incidence was significantly higher among European-American men (OR=3.3; 95%CI: 1.3-8.3), and among participants reporting a history of amphetamine use (OR=24; 95%CI: 6.9-83) or medical opioid use for treatment of pain (OR=8.6; 95%CI: 2.5-30). These associations remained strong when examined among marijuana users and after adjusting for demographics, social factors, and other antecedent substance use. Amphetamine use was the best single predictor of future nonmedical use (sensitivity 87%, specificity 79%).

CONCLUSIONS

Initiation of nonmedical prescription opioid use is generally rare in 28-40-year-old adults, but is observed to be more common with a previous history of substance abuse and legal access to opioids through prescription by a physician.