Lockdown has had a big impact on everyone but especially those who are in receipt of opiate prescribing treatments. Daily administration and prescription management has become increasingly difficult to sustain and contact time with key workers has become compromised for many. Now there is a game changer. Buvidal is a prolonged-release buprenorphine injection that can be administered as a weekly or monthly injection. Initially it was developed to reduce the risk of diversion of opioid substitution medicines or where there were concerns about the safety of medicines stored at home. It was also considered an option for people who have difficulties adhering to daily supervised opioid substitution medication, such as for people who are working or in education. However, in a time of lockdown, it can offer the opportunity for longer term stability in a period of uncertainty.
It has a marketing authorisation for treating opioid dependence in adults and young people aged 16 years and over within a framework of medical, social and psychological treatment. Buprenorphine prolonged-release injection is recommended up to a weekly maximum dose of 32 mg or monthly maximum dose of 128 mg, which is approximately equivalent to 18 mg to 24 mg daily of sublingual buprenorphine. Therefore it may not be suitable for people with opioid substitution requirements greater than this. A maximum of 1 additional 8‑mg dose can be given between regular weekly or monthly injections if needed, based on an individual person's temporary needs. Injection-site reactions can happen after the injection is given and around 17% of people in the trial experienced these.
Evidence of its effectiveness was identified in 1 randomised controlled trial (Lofwall et al. 2018 (click here). The treatment sample was 428 adults diagnosed with, and seeking treatment for, moderate to severe opioid use disorder. Overall, people using buprenorphine prolonged-release injection were no less likely to have opioid-negative urine samples or respond to treatment (defined as having no evidence of illicit opioid use at most assessments) compared with people using sublingual buprenorphine–naloxone. This was 35.1% for buprenorphine prolonged-release injection compared with 28.4% for sublingual buprenorphine–naloxone tablets.
Furthermore, Buvidal prolonged-release injection was non-inferior to sublingual buprenorphine–naloxone tablets for the responder rate (a responder had no evidence of illicit opioid use at most assessments over 24 weeks). This was 17.4% for Buvidal compared with 14.4% for sublingual buprenorphine–naloxone.
In Lofwall et al. (2018), the most common adverse events in the buprenorphine prolonged-release injection group were injection-site pain (8.9%), headache (7.5%), constipation (7.5%), nausea (7.0%), injection-site pruritus (6.1%) and injection-site erythema (5.6%). These were also the most common adverse events in the sublingual buprenorphine–naloxone (placebo injection) group, with similar proportions of participants experiencing these. Insomnia was reported by slightly more people in the buprenorphine prolonged-release injection group compared with the sublingual buprenorphine–naloxone group (5.6% compared with 2.8%). No statistical analyses were reported.
The summary of product characteristics states that deaths from respiratory depression have been reported in people having treatment with buprenorphine, particularly when used in combination with benzodiazepines. Deaths have also been reported when buprenorphine is used in combination with other depressants (such as alcohol), pregabalin and gabapentin, or other opioids.
Once administered, the prolonged-release injection dose cannot be removed. In the case of overdose, the long duration of action of buprenorphine along with the prolonged-release properties of the subcutaneous injection should be taken into account when determining length of treatment needed to reverse the effects of overdose.
However, there are limitation to the evidence. Currently the evidence is drawn from one US study. In the UK, the most common opioid misused by around 70% of participants at baseline was heroin, which reflects the UK population where heroin is the main problem drug of most adults who misuse drugs. And there are care transition procedures to move people from methadone to buprenorphine before Buvidal can be administered.
Whilst Buvidal was due to be piloted in a in number of areas across the UK, lockdown has seen an acceleration of this process. It is likely to that it will rapidly establish itself as a standardised treatment in the coming months. However, the current limited evidence-base, combined with the unique situational pressures clients are currently under, it will be vital to closely monitor its impact.