ANAHEIM — For patients prescribed opioids, use of heroin was highly tied to use of other illicit drugs, researchers reported here.
Among a collection of 171,061 urine samples from patients prescribed opioid therapy, about 1.3% also tested positive for heroin use, according to Mancia Ko, PharmD, MBA, of Ameritox, LLC, a company in Baltimore that provides physicians with urine drug monitoring and reporting services.
Most notable, however, the investigators said, was that heroin use was strongly tied to use of other drugs — for example, a 12.8 higher odds of use of cocaine (19.2% versus 1.8%, 95% CI 11.4-14.3), and a 2.2 higher odds of testing positive for tetrahydrocannabinol (THC) (12.5% versus 9.0%, 95% CI 1.9-2.5) compared with those who did not use heroin.
The findings were presented at the American Pain Society’s Scientific Summit.
“Four out of five heroin users started with prescription opioids,” Ko told MedPage Today during the poster session that included the study. “But another starting point is that patients are getting more tolerant, so they are abusing heroin, which is purer and cheaper to get their psychoactive high compared to just prescription-strength medication.”
The 2-year study tested patients’ urine samples for the metabolite 6-monoacetylmorphine using liquid chromatography/tandem mass spectrometry. Individuals prescribed morphine, buprenorphine, or methadone were excluded from the analysis. The samples were then tested for other drugs, including cocaine; phencyclidine (PCP, “angel dust); THC; 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”); synthetic cathinones; and synthetic cannabinoids.
Patients prescribed opioid therapy who tested positive for heroin use were more likely to be younger, male, and insured by Medicaid, the researchers found.
The analysis also determined adherence to prescribed opioid therapy, including opiates, stimulants, synthetic opioids, and sedatives and hypnotics.
Interestingly, those on opioid therapy were 2.8 times less likely to be adherent to their prescribed opiates (56.5% versus 31.6%) or sedative hypnotics (28.2% versus 12.3%) if they tested positive for heroin. Similarly, heroin use was tied to a 1.6 times higher chance of adherence to prescribed synthetic opioids (5.3% versus 3.3) — a finding that Ko called surprising.
Similarly, heroin users were also more likely to test positive for opioids that were not prescribed to them versus those who did not use heroin, as follows:
- Opiates and synthetic opioids: OR 6.8 (95% CI 6.1-7.5)
- Stimulants: 2.7 (2.2-3.2)
- Sedative/hypnotics: 1.4 (1.3-1.6)
“The gist of it is to really encourage clinicians to not only test patients whom they think subjectively may not be taking [a drug] or only test for one particular medication that’s on the medication chart — they should look at it more comprehensively, because as you can see, there are other risk factors that may lead them to better proactively figure out where the patients are in terms of their medication use pattern,” Ko said.
Possible limitations to the analysis, the researchers said, include the possibility of selection bias due to physicians’ testing patients who are suspected of misuse.
In the future, Ko said, the team hopes to assess use of other types of illicit substances that patients prescribed opioid therapy may be utilizing beyond heroin, cocaine, and cannabis.
Ko is an employee of Ameritox, LLC.