Drug users who inject heroin after completing 21-day methadone programs or after release from jail or prison may have a high risk of overdose, according to UCSF researchers. The researchers explained that lowered tolerance levels in each of these situations may increase overdose risk.
Researchers with the Urban Health study in the UCSF Department of Family and Community Medicine and the Institute for Health Policy Studies also noted that among heroin injectors, the use of substances such as sedatives and alcohol that contribute to central nervous system depression may promote high risk injection behavior and enhance the respiratory depressant effects of heroin.
â€śOur findings highlight the critical importance of including overdose prevention education in 21-day methadone detoxification clinics and pre-release programs in jails and prisons,â€? said Karen H. Seal, MD, MPH, UCSF assistant professor of family and community medicine and lead author of the study, which appears in the November issue of the American Journal of Public Health.
Four characteristics were independently associated with recent overdoses in a San Francisco Bay Area population, according to researchers. These characteristics include: 1) being homeless, 2) having spent five or more years in jail or prison 3) identifying as lesbian, gay, bisexual or transgendered, 4) and having engaged in sex work for money or drugs in the last six months.
The researchers added that being relatively younger, having been arrested three or more times in the past year, and drinking four or more alcoholic drinks per day were also independently associated with overdose in the last year.
â€śSocially marginalized heroin injectors who lack a stable community, a safe place to inject, and a steady and known supply of heroin may be more likely to inject alone, rush injections because of fears of arrest, and to experience fluctuations in heroin purity and tolerance â€“ all of which may culminate in a greater tendency toward overdose,â€? said Seal.
From August 1998 through July 1999 UCSF investigators recruited 1,427 heroin users from six inner city neighborhoods in the San Francisco Bay Area. The median age of study participants was 44 years; 31 percent were female; 51 percent self-identified as African American, 35 percent as white, 7 percent as Latino and 7 percent as Asian or Pacific Islander, mixed, or â€śotherâ€? race/ethnicity. The median duration of injection drug use was 24 years. Among study participants, 48 percent reported an overdose, 33 percent had experienced two or more overdose events, and 13 percent reported an overdose within the last year.
Since 1986, the Urban Health Study has conducted semi-annual surveys of injection drug users (IDUs) to carry out HIV and hepatitis surveillance and provide risk reduction counseling. Participants are recruited from street settings by experienced outreach workers.
Eligibility for this study was based on reporting recent injection drug use (past 30 days). Participants were interviewed by trained counselors about demographics and sexual and injection risk behavior, including overdosing. For this analysis, researchers restricted their sample to the 1427 participants who reported injecting heroin or â€śspeedballsâ€? (a cocaine and heroin mixture) in the past six months.
According to researchers, heroin overdose has been increasing dramatically in the United States. From 1990 to 1995, heroin-related emergency department visits doubled from 33, 884 to 70, 838. Deaths from overdose more than doubled in the last decade in two counties in Oregon and Washington states. Increasing purity of heroin, coupled with declining street prices has compounded the problem, according to Seal.
â€śData tell us that targeted interventions that decrease the risk of overdose are urgently needed,â€? she said.
Additional researchers on this study (all affiliated with the UCSF Urban Health Study in the UCSF Department of Family and Community Medicine and the Institute for Health Policy Studies) include: Alex H. Kral, PhD, assistant professor of family and community medicine; Lisa D. Moore, Dr.PH, project director; Jennifer Lorvick, BA, project director; and Brian Edlin, MD, director of Urban Health Study.
This study was funded by a contract from the San Francisco Department of Public Health and a grant from the National Institute on Drug Abuse.