Background: Opioid agonist therapy with buprenorphine is an effective, evidence-based treatment for opioid use disorder. However, there has been increasing use of alternative substances which can still produce opioid-like effects. One of these substances is the herbal supplement kratom. The chemical composition of kratom, specifically mitragynine and 7-hydroxymitragynine, has partial mu-opioid receptor agonist and antagonist effects at the kappa- and delta-opioid receptors. Due to its addictive potential, accessibility, and legal status, there have been increasing cases of kratom use disorder (KUD). Thus, it is important to consider effective treatment options for this nontraditional substance. Methods: Twenty-eight patients self-identified kratom as their primary substance of use. Length of kratom use ranged between 1 month and 25 years, with an average daily kratom dose of 92 g/d. Nine patients were inducted on a buprenorphine/naloxone dose between 1 and 6 mg, 18 patients between 8 and 16 mg, and 1 patient at 20 mg. Three patients were stabilized on a dose at 4 mg, 23 patients between 8 and 16 mg, 1 patient at 18 mg, and 1 patient at 20 mg. Results: There was no correlation between stabilizing dose of buprenorphine/naloxone and past daily dose of kratom. As of March 2020, 20 of the 28 patients were still receiving outpatient buprenorphine/naloxone treatment. Six patients were lost to follow-up due to missed appointments, 1 tapered down to 0.25 mg of buprenorphine/naloxone and self-discharged, and 1 moved out of town. The rest have remained in treatment from 5 to 22 months, with an average duration of 11 months. Of the 28 patients, 68%, 82%, and 82% had negative test results for mitragynine at 4, 8, and 12 weeks of treatment, respectively. Conclusions: To our knowledge, this is the largest case series exploring long-term buprenorphine/naloxone treatment for KUD. Our findings suggest buprenorphine/naloxone can be used as an effective treatment option for KUD.
Keywords: Kratom; buprenorphine; opioid agonist.