Stimulants such as methamphetamine and cocaine are frequently used to manage non-cancer chronic pain, particularly in people with neuropathic pain and among women, according to research published in Substance Abuse.
Some clinical and in vivo studies across pain types suggest that stimulants may possess analgesic properties. Qualitative studies have reported on the prevalence of cocaine or methamphetamine use to manage pain in people living with HIV.
To evaluate the relationship between pain management and stimulant use in people with chronic pain, researchers conducted an exploratory analysis of the characteristics associated with reporting stimulant use in patients enrolled in the COPING (Cohort Study of Opioids, Pain, and Safety in an era of Changing Policy) study. COPING is an ongoing, longitudinal cohort study that assesses changes in pain, functional status, and substance use in response to changes in the availability of prescribed opioids in patients with chronic noncancer pain.
For the current study, researchers used the available baseline data. Stimulant use was defined as any reported use of methamphetamine or speed, cocaine, or crack cocaine in the prior year. Of the 440 eligible participants, 300 enrolled in the current study (mean age, 57±8.2 years; 61% men; 45% Black or African American; 77% had experienced homelessness).
Roughly 35% of COPING participants reported illicit stimulant use in the past year; 37% of them used cocaine or crack cocaine, 31% had used methamphetamine (or speed), and 31% used both cocaine or crack cocaine and methamphetamine. Eight participants reported using prescription stimulants not prescribed to them, in addition to nonprescription stimulants during the study period.
Among those who reported methamphetamine use, 35% used it less than once a month, 27% used 1 to 3 days a month, 11% used 1 to 2 days per week, 6% used 3 to 4 days, 6% used it 5 to 6 days per week, and 15% used every day. Among those who reported cocaine or crack-cocaine use, 29%, 24%, 22%, 13%, 6%, and 7% used in the same time periods.
Participants who reported past-year stimulant use were, generally, slightly younger (mean age, 56±8.5 vs 58±7.9) and more were HIV-positive (54% vs 25%). Gender differed significantly, with a higher proportion of past-year users being men (69% vs 56%) or transgender/other gender (5% vs 3%), while a lower proportion of women reported use in the past year (27% vs 41%) compared with those who did not use stimulants.
A high proportion of participants who used stimulants also reported ever being homeless (86% vs 72%), but 92% of participants who used stimulants did report being housed for most of the past year.
Just over half (52%) of those who reported past-year stimulant use reported using stimulants to treat pain. Those who reported stimulant use to treat pain generally had attained a higher level of education (62% vs 42%) and ever being homeless (93% vs 78%) compared with participants who reported stimulant use not for pain management purposes. Those who reported pain management-related stimulant use also reported experiencing either moderate or severe depression (49% vs 28%).
No difference was detected in cold pain threshold or tolerance (median, 7.48 and 13.2, respectively). No difference was seen in the use of neuropathic pain medications or medical marijuana across groups, but a higher proportion of participants who used stimulants for pain management subsequently reported the prescription of other nonopioid pain management medications such as acetaminophen or nonsteroidal anti-inflammatory drugs (42% vs 20%).
Results of a multivariable regression analysis found that Douleur Neuropathique 4 (DN4) score and being a woman were significantly associated with stimulant use to manage pain. Every 1-point increase on the DN4 scale was associated with a 1.34 times adjusted odds of reporting stimulant use to treat pain (95% CI, 1.05-1.70), while women had a 3.20 times adjusted odds compared with men (95% CI, 1.06-9.63).
Study limitations include a lack of generalizability outside of patients in the San Francisco Bay area who were prescribed opioids for chronic pain and have a history of illicit substance use; the use of self-reported data that concern sensitive and illegal behaviors, which may have skewed the available information; and no measurement of concurrent or sequential opioid use.
Future studies, the researchers wrote, should “investigate polysubstance use for nonmedical reasons or for self-medication, and should look at patients longitudinally to understand the temporal relationship between opioid stewardship and stimulant use for pain.”
“To our knowledge, this is the first report focusing on stimulant use for pain self-management,” the researchers concluded. “Our findings provide an opening for providers to engage in discussions with their patients regarding their use of stimulants as a possible part of pain self-management routines.”
Beliveau CM, McMahan VM, Arenander J, et al. Stimulant use for self-management of pain among safety-net patients with chronic non-cancer pain. Subst Abus. Published online April 2, 2021. doi:10.1080/08897077.2021.1903654