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.

Oral ketamine as a positive control in human abuse potential studies.

The selection of a relevant and appropriate positive control is of key importance in the design of a clinical abuse potential study. Ketamine is a N-methyl-d-aspartate receptor antagonist used clinically as an anaesthetic, yet also abused for its euphoric and perceptual properties. The current study sought to identify 2 doses of oral ketamine that are safe and produce subjective effects that would make them suitable for use as positive controls in abuse potential studies. A single-center, partially double-blind, placebo-controlled, ascending dose (65, 100 and 150 mg) study was carried out in 11 healthy recreational polydrug users who first passed a pharmacologic qualification session to ensure they could distinguish and like the effects of a psychoactive drug (20mg d-amphetamine) compared to placebo. Subjective data were collected through questionnaires (e.g., Addiction Research Center Inventory [ARCI] scales) and visual analog scales (VAS). Generally, oral ketamine was well tolerated and could be used safely at 65 mg and 100mg. Peak responses to ketamine were significantly different (p<0.05) from placebo on measures of positive (e.g., drug liking VAS), perceptual (e.g., VAS of floating, detached, hallucinating) and sedative (e.g., ARCI phenobarbital-chlorpromazine-alcohol group scale) effects. Effects were generally not dose-dependent, though significant differences for some subjective effects measures were observed between 65 mg and 100mg ketamine. The current study indicates that oral ketamine doses of 65 mg and 100mg are useful positive controls for future abuse potential studies of compounds with a similar mechanism of action, or with possible perception-altering and euphoric effects.

Mood changes during pregnancy and the postpartum period: development of a biopsychosocial model.

OBJECTIVE: Women are vulnerable to mood changes during pregnancy and the postpartum period. We set out to empirically test the hypothesis that biological and psychosocial variables interact to result in this vulnerability. METHOD: Using structural equation modeling techniques, we developed an integrative model of perinatal mood changes from clinical, psychosocial, hormone and mood data collected from 150 women in late pregnancy and at 6-weeks postpartum. RESULTS: In the prenatal model, biological variables had no direct effect on depressive symptoms. However, they did act indirectly through their significant effects on psychosocial stressors and symptoms of anxiety. The same model did not fit the postpartum data, suggesting that different causal variables may be implicated in postpartum mood. CONCLUSION: This model demonstrates the importance of considering both biological and psychosocial variables in complex health conditions such as perinatal mood disorders.

Measurement issues in postpartum depression part 2: assessment of somatic symptoms using the Hamilton Rating Scale for Depression.

Assessment of the somatic symptoms of depression in perinatal women has been debated due to potential overlap with normal physical complaints of pregnancy and childbirth. We investigated the properties of the 17-item Hamilton Rating Scale for Depression (HAMD), which includes somatic items, between 36 weeks gestation and 16 weeks postpartum in 150 women. Scores on the HAMD were highly correlated with scores on measures that avoid somatic items. Scores on somatic items were not well correlated with the total HAMD score in pregnancy, but the correlations increased at 6 weeks postpartum. In contrast, scores on HAMD item 1 ("Depression") were less well correlated with the total score at 6 weeks postpartum than prenatally, suggesting that postpartum women may be less likely to articulate their difficulties as "depression", and more likely to describe somatic complaints such as low energy or insomnia. Implications for the assessment of depression in this population are discussed.

Measurement issues in postpartum depression part 1: anxiety as a feature of postpartum depression.

We investigated the contribution of anxiety symptoms to scores on the Edinburgh Postnatal Depression Scale (EPDS) between 36 weeks gestation and 16 weeks postpartum in 150 women. The 3-item anxiety subscale of the EPDS accounted for 47% of the total score in late pregnancy, and 38% of the total score in the postpartum period. Two categories of anxiety were common in the perinatal period: subsyndromal, situational anxiety (in particular during the last weeks of pregnancy); and clinically significant comorbid anxiety, which was experienced by nearly 50% of clinically depressed pregnant and postpartum women. The close relationship between anxiety and depression raises questions about whether symptoms of anxiety might be more common in the perinatal period than in other depressions. A strong role for anxiety symptoms in postpartum depression, and implications for its etiology and treatment, are discussed.

Cognitive toxicity of drugs used in the elderly.

The aged are an extremely heterogeneous population that is growing worldwide, included are healthy and agile individuals in their early sixties, as well as an increasing number of people over the age of 35. Pharmacotherapy is expected to continue its prominent role in the medical management of a wide range of conditions that affect older people. Adverse consequences of all kinds complicate the use of medications, and such events seem to increase in incidence with polypharmacy. Cognitive impairment can occur during the course of treatment with a wide range of medications and can have a variety of presentations, Both the number of concurrent medications that older individuals routinely use and physiologic changes in these patients render them more susceptible to developing cognitive toxicity. Most of the frequently implicated medications carry documentation of their ability to cause cognitive disturbances in their package labeling, suggesting that the level of vigilance for adverse effects during the course of their use should always be high. Such caution can be used to guide appropriate drug treatment of the aged so that clinicians do not need to opt for undertreatment to avoid toxicity.

Efficacy of dexfenfluramine in the treatment of alcohol dependence.

BACKGROUND: A substantial body of evidence supports a role for serotonin in modulating alcohol intake, which suggests that this neurotransmitter represents a promising target for pharmacotherapy development for alcohol use disorders. Dexfenfluramine. a serotonin releaser and reuptake inhibitor, decreases alcohol self-administration by rats. Its greater potency and several mechanisms of action suggest it should be more effective in treating alcohol dependence than drugs that only inhibit serotonin reuptake. METHODS: We conducted an 11 week, randomized, double-blind trial that compared oral placebo and dexfenfluramine 7.5, 15, 22.5, and 30 mg bid in 136 alcohol-dependent patients. A brief behavioral intervention was offered concurrently. RESULTS: The majority of subjects were male (72%), and the age of the group was 44 +/- 1 years (mean +/- SD). Both placebo- and drug-treated groups significantly reduced alcohol consumption compared with baseline (a 55% decrease in mean drinks per day; p < 0.01), but there were no significant differences between drug and placebo groups or dose effects for most outcome measures. CONCLUSIONS: Our results with dexfenfluramine are further evidence that serotonergic medications on their own do not significantly reduce alcohol consumption in alcohol-dependent individuals. Combination pharmacotherapy with agents that act on different receptors or neurotransmitter systems (e.g., naltrexone plus dexfenfluramine) may be one way to enhance serotonergic effects on drinking behavior and should be considered in future medication development clinical trials.

Inhibition of cytochrome P450 2D6 modifies codeine abuse liability.

Oral codeine preparations, widely used for analgesia and cough suppression, are abused by some individuals for their mood-altering properties. The enzymatic O-demethylation of codeine is catalyzed by cytochrome P450 2D6 (CYP2D6), leading to the production of metabolites (morphine, morphine-6-glucuronide) that are pharmacologically more potent than codeine. A placebo-controlled, single-blind study was conducted to characterize the subjective effects of codeine associated with abuse liability and to determine the importance of metabolic O-demethylation to codeine abuse liability. Twelve non-drug-dependent subjects received oral administration of placebo and codeine 60, 120, and 180 mg, and a favorite dose (FD) was determined for each subject. The FD was readministered after pretreatment with placebo, 50 mg of quinidine (a specific, selective CYP2D6 inhibitor) once, or 50 mg of quinidine given four times a day for 4 days. Single-dose quinidine pretreatment significantly decreased the recovery of O-demethylated metabolites in plasma (p < 0.01) and resulted in a decrease in the positive (e.g., "high," p < 0.05) and negative (e.g., nausea, p < 0.05) subjective effects of codeine in both the FD120 and FD180 groups. Short-term quinidine pretreatment inhibited codeine O-demethylation more than did single-dose quinidine pretreatment (p < 0.01), and it decreased positive codeine effects in the FD120 group (N = 7), but unexpectedly not in the FD180 group (N = 5). These results suggest that the O-demethylated metabolites contribute substantially to the subjective effects and abuse liability of codeine.

Cytochrome P450 2D6 and treatment of codeine dependence.

Oral opioid analgesics such as codeine are used extensively worldwide and are frequently misused. Codeine is a substrate of CYP2D6, a genetically polymorphic P450 enzyme, and is metabolized to the more potent drug morphine. CYP2D6 activity can be inhibited by fluoxetine, and the inhibition of morphine formation may help individuals reduce their use of codeine. Fourteen long-term users of oral opiates (principally codeine) were assessed for an open-label pilot treatment study of fluoxetine 20 mg/day combined with a brief behavioral intervention and structured tapering of the opiate. Eight subjects entered and completed the 8-week treatment. Opiate use decreased by 30% to 100% of baseline use (p < 0.0001) in parallel with a decrease in CYP2D6 activity. Fluoxetine may have a role in the treatment of opiate dependence by decreasing opiate-reinforcing properties.

Attenuation of the euphoric effects of cocaine by the dopamine D1/D5 antagonist ecopipam (SCH 39166)

BACKGROUND: The subjective and reinforcing effects of cocaine in humans are associated with the enhancement of endogenous dopamine function in the mesolimbic system. This study examined the role of dopamine D1-like receptors in the behavioral and mood effects of cocaine by evaluating the effects of the selective D1/D5 antagonist ecopipam (SCH 39166) on subjective responses to intravenous cocaine in 11 subjects with cocaine dependence as defined by DSM-IV. METHODS: Subjects were pretreated in a randomized double-blind fashion with either placebo or 10 mg, 25 mg, or 100 mg of ecopipam orally on 4 separate occasions. Two hours later a single intravenous injection of 30 mg of cocaine was administered. Subjective and cardiovascular responses were measured and blood samples for pharmacokinetic evaluation were obtained prior to cocaine dosing and at various times after dosing. RESULTS: The euphoric (P = .004) and stimulating (P = .03) effects of cocaine were attenuated in a dose-dependent manner by ecopipam, while ratings of desire to take cocaine were diminished (P = .02). Ecopipam in combination with cocaine was safe and well tolerated. CONCLUSION: These data indicate a potentially important role for D1-like receptors in the acute mood-altering and rewarding effects of cocaine in humans.

Risk of drug dependence and abuse posed by barbiturate-containing analgesics.

Concern has been raised that the barbiturate component of barbiturate-containing analgesics constitutes a public and individual health problem because of information from literature before 1966 concerning preclinical and clinical abuse liability, and the dependence risk of barbiturates. The safety of barbiturates alone and in combination in analgesics was reviewed. In addition, information from manufacturers of combination products were evaluated. A meta-analysis was not possible because of the paucity of formal clinical trials. Even though barbiturates have a narrow margin of safety and substantial abuse potential, there is no evidence that barbiturate-containing analgesics without codeine represent a public health or social problem because of their abuse potential. However, proper studies to confirm this theory have not been performed. In the absence of better data concerning efficacy and lack of dependence potential, barbiturate-containing analgesics are not first-line medications for the initiation of treatment for pain. Codeine-containing combination analgesics have the potential to be a more important public health problem than those with only barbiturate in the combination.

Characteristics of dependent and nondependent regular users of codeine.

Although codeine is a widely used medication, the problems of codeine abuse and dependence have not been well-studied. This study characterized regular codeine users (using at least 3 days per week for 6 months, excluding those using codeine for the treatment of cancer pain) through a self-completed questionnaire. Recruitment through newspaper advertisements resulted in a total of 339 eligible questionnaires. Thirty-seven percent of subjects met DSM-IV criteria for codeine dependence. Dependent subjects (mean age, 40 +/- 10 years) were using an average of 179 (+/-171) mg of codeine per day. Codeine was predominantly used in the form of combination products with acetaminophen. Dependent subjects identified specific problems causally related to their codeine use such as depression (23%), anxiety (21%), and gastrointestinal disturbances (13%). The dependent subjects reported problems with other drugs more than did nondependent users (alcohol, 57% vs. 26%; cannabis, 23% vs. 5%; sedative/hypnotics, 33% vs. 12%; and heroin, 11% vs. 2%, respectively). Most were taking codeine primarily for a chronic pain problem (81%), although the dependent subjects currently found codeine less effective for treating pain than did the nondependent subjects and were more likely to use codeine for pleasurable effects, to relax, or to prevent withdrawal symptoms. This study showed that dependence is associated with the regular use of codeine. Pain is a key issue with these users; however, they are probably not receiving optimal treatment. There is a need to identify individuals experiencing problems with their codeine use and to develop optimal prevention and treatment strategies.

Long-term codeine use is associated with depressive symptoms.

A community survey was conducted among long-term (>6 months) users of codeine-containing products to characterize chronic use of these extensively consumed medications. Respondents recruited through newspaper advertisements completed a mailed questionnaire. Three hundred thirty-nine completed questionnaires were obtained, yielding a response rate of 70%. Codeine dependence/abuse as defined by DSM-IV criteria was present in 41% of the respondents. Two thirds of the subjects had sought help for mental health problems, most often depression (70%). Scores on the Symptom Checklist-90 subscales were modestly elevated, particularly on the Depression subscale (1.2 +/- 0.9). Long-term codeine use is strongly associated with dependence. Depression and depressive symptoms are common. These data suggest that dysphoric mood states may be significant in maintaining long-term codeine use.

A controlled trial of ondansetron, a 5-HT3 antagonist, in benzodiazepine discontinuation.

Serotonin is implicated in the etiology of anxiety disorders and in the anxiolytic actions of benzodiazepines. Preclinical studies with 5-HT3 receptor antagonists, including ondansetron, show they have anxiolytic properties and that ondansetron suppresses withdrawal anxiety after abrupt discontinuation of chronic benzodiazepine treatment. We evaluated the efficacy of ondansetron as an adjunctive medication in the discontinuation of benzodiazepines in long-term users. One hundred eight patients who had used alprazolam or lorazepam regularly for > 3 months entered, and 97 completed a randomized double-blind discontinuation treatment program during which they received either ondansetron 2 mg twice daily or placebo and flexibly tapered their benzodiazepine over a 6-week period. There were no significant differences between the patients who had entered and completed treatment. Three weeks postmedication, 63% of the patients discontinued use of benzodiazepine. The percentage of reduction of benzodiazepine daily dosage at all time points in the treatment trial was similar for the ondansetron and placebo groups. Ondansetron had no significant effects on severity of withdrawal symptoms or levels of anxiety. High placebo response may have prevented detection of an ondansetron effect. At 1 year follow-up, 68% of patients reported that they stopped using benzodiazepine. Patient characteristics were more important than ondansetron in tapered benzodiazepine discontinuation.

CYP2D6 inhibition in patients treated with sertraline.

Sertraline, a selective serotonin reuptake inhibitor used to treat depression, inhibits CYP2D6 in vitro (Ki = 1.2 microM) less potently than fluoxetine (Ki = 0.15 microM). To determine the extent and time course of CYP2D6 inhibition in patients, six males (mean age: 40 years, range: 29-64 years), who were starting treatment for depression with sertraline, were phenotyped on five occasions (once before treatment and approximately 3, 7, 14, and 21 days later). Phenotype status was determined using oral dextromethorphan (30 mg) by calculating the urinary ratio of O-demethylated metabolites to parent drug (i.e., log ODMR). CYP2D6 genotype was determined by leukocyte DNA analysis using polymerase chain reaction amplification. Compliance was confirmed by sertraline plasma levels. Daily sertraline dosages ranged from 50 to 150 mg. Genotype results indicated all subjects were extensive metabolizers (four homozygous wild type [wt], two heterozygous wt/B mutation). Phenotype results showed that CYP2D6 inhibition in patients treated with sertraline appeared to be related to baseline CYP2D6 activity and sertraline dosage. Some patients with high CYP2D6 activity can demonstrate inhibition with sertraline dosages as low as 50 mg.

Multiple drug use and psychiatric comorbidity in patients admitted to the hospital with severe benzodiazepine dependence.

This study aimed to evaluate the concurrent and lifetime psychiatric comorbidity and drug use patterns in patients admitted to the hospital for detoxification from benzodiazepines. Psychiatric assessments using the Structured Clinical Interview for DSM-III-R with a psychosis screening module (SCID-P and II) were conducted in 30 inpatients admitted to the medical unit treatment unit of the Clinical Research and Treatment Institute of the Addiction Research Foundation for the treatment of severe benzodiazepine dependence. Patients (mean age, 36 years; range, 22-58; number of DSM-III-R criteria met for benzodiazepine substance dependence, > or = 7 out of 9 [73%], all 9 criteria [40%]) used benzodiazepines and other drugs over prolonged periods of time at high doses, and their daily functioning was substantially impaired (Mean Global Assessment of Functioning Score, 48; range, 31-60). The most common lifetime psychiatric diagnoses were major depression (33%), other psychoactive drug dependence (100%) (opioids, 77%; alcohol, 53%), and panic disorder (30%). Current psychiatric diagnoses in addition to benzodiazepine dependence included other psychoactive substance use disorders (83%) (opioids, 67%; cocaine, 13%; multiple concurrent substance use, 17%), panic disorder (13%), and generalized anxiety disorder, (20%). Personality disorders included antisocial (42%), avoidant (25%), and borderline (17%). These findings demonstrate that in patients severely dependent on benzodiazepines, additional psychoactive substance use and mental disorders are prominent. The pattern of drug use and psychiatric comorbidity differentiates these patients from therapeutic-dose benzodiazepine users.

Clinical efficacy of the 5-HT3 antagonist ondansetron in alcohol abuse and dependence.

Medications that act on the serotonergic system have been found to be of benefit in the treatment of alcohol-dependent individuals. In a randomized, placebo-controlled study, the efficacy of 6 weeks of ondansetron, a 5-HT3 antagonist (0.25 mg bid or 2.0 mg bid), in the treatment of 71 nonseverely alcohol-dependent males was tested. The results showed reduction of drinking differences were steadily increasing toward the end of the treatment period approached significance at week 7 in the 0.25 mg group (p = 0.06). Twice as many patients in this group showed > or = 2 standard deviations decrease in drinking compared with the other groups. When patients drinking > 10 drinks/drinking day at baseline (n = 11) were excluded from the analysis, significant group differences were found at both treatment and follow-up, with the lower ondansetron dose producing the greatest reduction from baseline (i.e., 2.8 standard drinks; -35% compared with baseline and -21% compared with placebo; p < 0.02-0.001). Within this group, there was an almost 4-fold greater number of patients showing a clinically meaningful decrease in drinking. Lower baseline drinking and higher level of education were significant and strong predictors of drinking reduction during treatment. Ondansetron was very well tolerated; hence, further long-term studies with 5-HT3 antagonists alone or in combination with other treatment components may offer promise for treatment of alcoholism.

Alprazolam and benzodiazepine dependence.

The incidence of nonmedical use of alprazolam is very low relative to its widespread legitimate medical use; in fact, given the millions of patients who have received this medication, the incidence is remarkably small. In particular, among patients with anxiety disorders, dependence does not appear to be a clinically important problem. Alprazolam abuse and dependence represent only a small fraction of the large and serious nonmedical use problem in the United States, and when they occur, are among individuals who abuse other drugs. For example, a serious problem of alprazolam abuse may exist among patients in methadone maintenance treatment. A similar problem exists with diazepam. Alcohol abusers and alcohol-dependent individuals are another group among whom concern about benzodiazepine and alprazolam abuse exists. However, more and better information about the extent and nature of this use is needed. Many patients with alcohol or drug abuse also have anxiety disorders for whom effective pharmacotherapy may be needed. In the interim, caution but not prohibition to use should prevail in prescribing alprazolam to such patients. To the extent that nonmedical alprazolam use exists, evidence suggests that the vast majority of such use is the consequence of the inappropriate prescribing of the medication by a small number of physicians. One way to reduce the inappropriate use of benzodiazepines in methadone programs is to drug test the methadone-maintenance patients and to link positive urine tests to contingency-management strategies. The available data provide some support to the idea that alprazolam and diazepam have more abuse liability than other benzodiazepines.