Abstract : Buprenorphine and methadone are the two main opioid agonist treatments approved
for opioid use disorder. Buprenorphine is a partial agonist of the mu opioid
receptors, which has been merely available through sublingual form until now. In
practice, the use of buprenorphine is smoother than that of methadone, and it
induces reduced risks of overdose. However, sublingual buprenorphine also exposes
to risks (e.g., withdrawal, misuse) and constraints (e.g., daily intake). Three
new galenic formulations of prolonged-release buprenorphine (PRB) are being
commercialized and should allow some improvements in patients' comfort and
safety. This narrative review aims to describe the main technical features and
efficacy and safety data of these PRBs, as well as patients' and professionals'
expectancies and concerns, using data of the scientific literature and the
regulatory texts. PRBs consist of one subcutaneous implant and two subcutaneous
injection depots. Sixmo(R)/Probuphine(R) is a six-month-long implant which needs
to be surgically placed and removed and is approved for subjects previously
treated with a maximum daily dose of 8mg of sublingual buprenorphine, and can be
used only for two successive periods of six months before the subject needs to be
switched back to sublingual form. Sublocade(R) is a one-month-long depot
formulation that is indicated in switch from sublingual buprenorphine, and which
proposes only two dose schemes, i.e., 100 and 300mg monthly.
Buvidal(R)/Brixadi(R) is a one-week- or one-month-long depot formulation with
multiple dosages, which can be used in initiation or in switched from sublingual
formulations. While opioid users report some concerns with a risk of coercive use
of long-acting forms of buprenorphine, both users and professionals deem that
these new specialties could be particularly appreciated in stabilized patients
bothered with the daily intake of the treatments, or specific situations at risk
of treatment dropout (e.g., following hospital discharge or prison release).