|Authors: Walsh SL et al., JAMA Psychiatry 2017 Jun 22;
An investigational depot form of the medication has positive early results.
|The opioid receptor partial agonist buprenorphine, as sublingual monotherapy or in combination with the opioid antagonist naloxone (Suboxone), attenuates narcotic withdrawal and craving and blocks euphoria from concurrent narcotics. Still, buprenorphine is itself subject to misuse and diversion — the sublingual form prevents “cheeking” but not diversion by patients who take the medication home. These researchers examined whether a novel, non-FDA-approved, weekly injectable form of buprenorphine could eliminate these problems.
The manufacturer-sponsored, 3-week, phase II study enrolled otherwise healthy patients with moderate-to-severe opioid use disorder and physical dependence. After 4 to 7 days of treatment with oral morphine (allowing washout of illicit drugs), morphine was discontinued, and clinically meaningful test doses of intramuscular hydromorphone or placebo were administered. The 47 participants who rated “liking” of the drug substantially higher than placebo and demonstrated mild withdrawal after narcotic cessation were then randomized to 24 or 32 mg of depot buprenorphine (equivalent to 16 and 24 mg of sublingual buprenorphine, respectively). Two injections were given 1 week apart.
Both doses blocked liking of subsequent hydromorphone doses (large effect size) and narcotic withdrawal (medium-to-large effect size) through 1 week after the last injection. Buprenorphine continued to accumulate; other data have suggested that a steady state would be achieved after 4 weekly doses.