Nonmedical Prescription Opioid Users Transitioning to Heroin: Incidence and Predictors
Because of the concern about prescription opioid abuse and the growing numbers of dependent opioid users switching to heroin, it is of interest to ascertain the rate and incidence of such transition.
According to the National Institute on Drug Abuse, it has been estimated that 4-6% of abusers who misuse prescription opioids transition to heroin. A study, published by Carlson, et al, in 2016, found that over a 36-month period, 27 (7.5%) out of 362 initially non-opioid dependent illicit pharmaceutical opioid users initiated heroin use, with the rate of heroin initiation at 2.8 % per year.
Another report, published by Surratt, et al, in 2017, showed about 1 in 13 participants (7.7%) engaged in nonmedical prescription opioid use initiated heroin use.
Until more data are available, current evidence suggests a less than 10% incidence of nonmedical prescription opioid users transitioning to heroin abuse.
Carlson Study: Heroin Users in Columbus, Ohio
Access the study at: Carlson RG, et al. “Predictors of transition to heroin use among initially non-opioid dependent illicit pharmaceutical opioid users: A natural history study.” Drug Alcohol Depend 2016; 160: 127-134.
The study authors were from Wright State University Boonshoft School of Medicine, Center for Interventions, Treatment and Addictions Research and the Mailman School of Public Health, Columbia University, New York.
Between April 2009 and May 2010, the authors recruited 383 eligible participants from the Columbus, Ohio, area, a region that had experienced significant increases in the prescription opioid/heroin use when the current epidemic began around 2002.
Participant eligibility included:
- Age 18 to 23 years
- Self-reporting nonmedical prescription opioid use
- Expressing intentions to use illicit prescription opioids again
- Residence in Columbus area
- No lifetime opioid dependence
- No self-reported history of heroin use or history of drug injection
- No pending criminal charges
- No involvement in formal substance abuse treatment in the past 30 days
Baseline and follow-up structured questionnaires were conducted every 6 months for 36 months. Of the 383 participants interviewed at baseline, 89.8% returned at 6 months and then a slight decrease to 73.4% at 36 months. Analysis tested for association between predictors and hazard of transition to heroin use. Potential predictors were based on those suggested in the literature.
Over 36 months, 27 participants (7.5%) initiated heroin use, with a rate of 2.8% per year. Of those participants who switched to heroin use:
- All were white
- About 56% were male
- More than half had some post-secondary education
Four (14.8%) heroin initiates reported that their most frequent route of heroin administration was smoking, 11 (40.7%) reported sniff/snort, and 12 (44.4%) reported injection.
The mean length of prescription opioid use at first reported heroin use was 6.2 years.
Predictors of heroin initiation included three factors related to prescription opioid use:
- Developing lifetime opioid dependence (2.74 times the risk for heroin initiation)
- Having a higher lifetime maximum number of opioid dependence criteria (1.37 times the risk)
- A higher maximum frequency of prescription opioid use – 3 to 7 days per week vs 1 day per week (2.58 times the risk) or 3 to 7 days per week vs 2 days per week (2.87 times the risk)
An age-related predictor that was significant was 15 years or younger (3.12 times the risk). Other significant predictors of heroin initiation were alcohol dependence, ever reporting a non-oral use of prescription opioids, and ever having used sedatives, cocaine, stimulants, or Ecstasy.
According to the authors, at the time of its publication, this was one of the first prospective studies to examine the relationship between illicit prescription opioid use and heroin initiation among young, initially non-opioid-dependent, prescription opioid users. Also, according to the authors, many areas of the U.S. have experienced the evolution of the prescription opioid and heroin epidemics. The epidemics are an escalating public health crisis that require public health response proportionate in scale. Preventing transition to non-oral prescription opioid use, preventing transition to opioid dependence (by reducing frequency of prescription opioid use), and educating prescription opioid users about the risks involved while they are still non-opioid dependent are important intervention targets.
Surratt Report: Heroin Use in the Miami Club Scene
The study can be accessed at: Surratt HL, et al. “Heroin use among nonmedical prescription opioid users in the club scene.” Drug and Alcohol Dependence 2017; 179 (131-138).
The lead author was from the University of Kentucky Medical School, Lexington, with other contributors from NOVA Southeastern University in Miami; Case Western Reserve University in Cleveland, Ohio; and Washington University in St Louis, Missouri.
The report showed about 1 in 13 participants (7.7%) engaged in nonmedical prescription opioid use initiated heroin use. In their introduction, the authors stated that, although the dramatic rise in nonmedical prescription opioid use (NMPOU) that occurred in the U.S. from 1999 to 2010 has stabilized in recent years, the prevalence of prescription opioid use disorders and related mortality have continued to rise. Characterization of the opioid problem has indicated a shift from prescription opioids to heroin, with increasing rates of heroin use and overdose seen as early as 2009. With this in mind, the Surratt study investigated the initiation of heroin use over time among club goers in the Miami area who reported the nonmedical use of prescription opioids, and they examined the predictors of the transition to heroin that may be amenable to intervention.
Miami has for decades has been a key transportation hub and distribution center for illicit drugs. A study field office was set up and located for accessibility to primary transportation routes in the city. The trial protocol was designed to recruit a sample of 750 Miami-based, club-going participants and test the relative efficacy of low-intensity assessment interventions in reducing drug use and sexual risk behaviors at 3-, 6-, and 12-month follow-ups.
Study recruitment was conducted between September 2011 and November 2014, with respondents recruited through targeted outreach at Miami nightclub venues and contacts in the club scene derived from the authors’ prior Miami-based field studies.
At the time of baseline contact, the sample reported nonmedical prescription opioid use for a mean of 5 years.
The study documented heroin initiation in about 1 in 13 participants (7.7%) in the 12-month follow-up observational period. The mean age was 25 years, and 67.5% met the criteria for substance dependence. Most heroin initiators (60%) began using heroin at the 3-month interval, 24% started to use heroin at the 6 -month interval, and 16% reported initial heroin use at the 12-month interval. Only one participant not using prescription opiates indicated heroin onset at follow-up.
The following factors were associated with a greater likelihood of heroin initiation:
- Frequent LSD use
- History of drug overdose
- High frequency nonmedical prescription opioid use
- Using oral tampering methods
- Endorsing a primary medical source for prescription opioids
From those factors, the most significant predictors according to the statistical models of the study were LSD use, oral tampering, and having a primary medical source for opioids.
Relative to LSD use, each additional day of using LSD increased the hazard of initiating heroin use by 3%. Intervention strategies to reduce LSD use were not addressed by the authors.
The importance of oral tampering methods in club drug users and the association with heroin onset within one year may indicate the need to examine the role of abuse deterrent formulations (ADFs) in opioid prevention efforts. More widespread development of ADFs may have a significant role in preventing shifts in routes of administration.
The study demonstrated that participants who reported acquiring prescription opioids for nonmedical use through a primary medical source had substantially higher odds of endorsing heroin initiation at follow-up. While dealers and the sharing of medications presented much more common methods of opioid acquisition, a primary medical source for opioids conferred higher odds of heroin onset. Intervention strategies relative to the primary sources for opioids was not addressed by the authors.
From the three sources above, until more data are available, current evidence describes a less than 10% incidence of nonmedical prescription opioid users are transitioning to heroin abuse.
Richard L. Wynn, BS Pharm, PhD, is professor of pharmacology at the Baltimore College of Dental Surgery, Dental School, University of Maryland Baltimore.
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