This paper reviews studies examining the pharmacological interactions and epidemiology of the combined use of opioids and benzodiazepines (BZD). A search of English language publications from 1970 - 2012 was conducted using PubMed and PsycINFO®. Our search found approximately 200 articles appropriate for inclusion in this paper. While numerous reports indicate that the co-abuse of opioids and BZDs is ubiquitous around the world, the reasons for the co-abuse of these medications are not entirely clear. Though the possibility remains that opioid (ab)users are using BZDs therapeutically to self-medicate anxiety, mania or insomnia, the data reviewed in this paper suggest that BZD use is primarily recreational. For example, co-users report seeking BZD prescriptions for the purpose of enhancing opioid intoxication or “high,” and use doses that exceed the therapeutic range. Since there are few clinical studies investigating the pharmacological interaction and abuse liability of their combined use, this hypothesis has not been extensively evaluated in clinical settings. As such, our analysis encourages further systematic investigation of BZD abuse among opioid users. The co-abuse of BZDs and opioids is substantial and has negative consequences for general health, overdose lethality, and treatment outcome. Physicians should address this important and underappreciated problem with more cautious prescribing practices, and increased vigilance for abusive patterns of use.

These data provide new evidence of the feasibility, efficacy, and tolerability of long-lasting antagonist treatments for opioid dependence.

Symptoms of withdrawal after oral delta9-tetrahydrocannabinol (THC) administration have been reported, yet little is known about the development of dependence on smoked marijuana in humans. In a 21-day residential study, marijuana smokers (n = 12) worked on five psychomotor tasks during the day (0915-1700 hours), and in the evening engaged in recreational activities (1700-2330 hours); subjective-effects measures were completed 10 times/day. Food and beverages were available ad libitum from 0830 to 2330 hours. Marijuana cigarettes (0.0, 1.8, 3.1% THC) were smoked at 1000, 1400, 1800, and 2200 hours. Placebo marijuana was administered on days 1-4 . One of the active marijuana doses was administered on days 5-8, followed by 4 days of placebo marijuana (days 9-12). The other concentration of active marijuana cigarettes was administered on days 13-16, followed by 4 days of placebo marijuana (days 17-20); the order in which the high and low THC-concentration marijuana cigarettes were administered was counter-balanced between groups. Both active doses of marijuana increased ratings of "High," and "Good Drug Effect," and increased food intake, while decreasing verbal interaction compared to the placebo baseline (days 1-4). Abstinence from active marijuana increased ratings such as "Anxious," "Irritable," and "Stomach pain," and significantly decreased food intake compared to baseline. This empirical demonstration of withdrawal from smoked marijuana may suggest that daily marijuana use may be maintained, at least in part, by the alleviation of abstinence symptoms.

Symptoms of dependence and withdrawal after the frequent administration of high doses (210 mg/day) of oral delta9-tetrahydrocannabinol (THC) have been reported, yet little is known about dependence on lower oral THC doses, more relevant to levels attained by smoking marijuana. In a 20-day residential study, male (n = 6) and female (n = 6) marijuana smokers worked on five psychomotor tasks during the day (0915-1700 hours), and in the evening engaged in private or social recreational activities (1700-2330 hours); subjective-effects measures were completed 10 times/day, and a sleep questionnaire was completed each morning. Food and beverages were available ad libitum from 0830 to 2330 hours. Capsules were administered at 1000, 1400, 1800, and 2200 hours. Placebo THC was administered on days 1-3, 8-11, and 16-19. Active THC was administered on days 4-7 (20 mg qid) and on days 12-15 (30 mg qid). Both active doses of THC increased ratings of "High," "Good Drug Effect," and "Willingness to Take Dose Again" compared to baseline (days 1-3). THC also increased food intake by 35-45%, and decreased verbal interaction among participants compared to placebo baseline. Tolerance developed to the subjective effects of THC but not to its effects on food intake or social behavior. Abstinence from THC increased ratings of "Anxious," "Depressed," and "Irritable," decreased the reported quantity and quality of sleep, and decreased food intake by 20-30% compared to baseline. These behavioral changes indicate that dependence develops following exposure to lower daily doses of THC than have been previously studied, suggesting that the alleviation of abstinence symptoms may contribute to the maintenance of daily marijuana use.

Individuals seeking treatment for their marijuana use rarely achieve sustained abstinence.Objectives-To determine if THC, a cannabinoid agonist, and lofexidine, an α 2 -adrenergic receptor agonist, given alone and in combination, decreased symptoms of marijuana withdrawal and relapse, defined as a return to marijuana use after a period of abstinence.Methods-Nontreatment-seeking, male volunteers (n=8), averaging 12 marijuana cigarettes/day, were maintained on each of four medication conditions for 7 days: placebo, THC (60 mg/day), lofexidine (2.4 mg/day), and THC (60 mg/day) combined with lofexidine (2.4 mg/day); each inpatient phase was separated by an outpatient washout phase. During the first 3 inpatient days, placebo marijuana was available for self-administration (withdrawal). For the next 4 days, active marijuana was available for self-administration (relapse). Participants paid for self-administered marijuana using study earnings. Self-administration, mood, task performance, food intake and sleep were measured.Results-THC reversed the anorexia and weight loss associated with marijuana withdrawal, and decreased a subset of withdrawal symptoms, but increased sleep onset latency, and did not decrease marijuana relapse. Lofexidine was sedating, worsened abstinence-related anorexia, and did not robustly attenuate withdrawal, but improved sleep and decreased marijuana relapse. The combination of lofexidine and THC produced the most robust improvements in sleep, and decreased marijuana withdrawal, craving and relapse in daily marijuana smokers relative to either medication alone.Conclusions-These data suggest the combination of lofexidine and THC warrant further testing as a potential treatment for marijuana dependence. KeywordsMarinol; Britlofex; dependence; withdrawal; treatment; cannabinoid; norepinephrine Marijuana use is prevalent in American society, and the number of individuals who currently meet DSM-IV criteria for cannabis abuse or dependence has steadily increased since the 1990s (Compton et al., 2004). Although marijuana is less likely to produce dependence than drugs such as nicotine, alcohol or heroin (Anthony et al., 1994), the sheer number of marijuana smokers combined with the increasing potency of marijuana has NIH Public AccessAuthor Manuscript Psychopharmacology (Berl). Author manuscript; available in PMC 2012 June 12.Published in final edited form as:Psychopharmacology (Berl). 2008 March ; 197(1): 157-168. doi:10.1007/s00213-007-1020-8. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript resulted in a significant number of individuals developing cannabis use disorders, i.e., approximately 1.5% of the U.S. population (Compton et al., 2004).A number of studies have demonstrated that there is a personal (i.e., not court-mandated) demand for marijuana treatment, particularly when marijuana-specific treatment programs are offered (Roffman et al., 1988;Stephens et al., 1993;Lang et al., 2000). Treatmentseekers report distress about their marijuana use, and repeatedly ...