Long acting depot buprenorphine has been approved for the treatment of opioid dependence in Australia
The Therapeutic Goods Administration (TGA) in Australia has approved two long-acting injected depot buprenorphine medications: Buvidal™ and Sublocade™ The Buvidal™ product was listed on the PBS on 1 September 2019.
These formulations of buprenorphine are administered weekly or monthly
Buvidal™ is a modified release formulation of buprenorphine which is administered via subcutaneous (SC) injection in weekly or monthly intervals.
Sublocade™ is an extended-release formulation of buprenorphine which is administered via subcutaneous injection in monthly intervals.
What does this mean for General Practitioners (GPs)?
Increasing numbers of patients may present to GPs who are being treated with depot buprenorphine, which may have implications for patients’ other treatment needs.
Depot buprenorphine may reduce the effects of opioid analgesia
Buprenorphine, through its properties as a partial agonist at opioid receptors, may reduce the effects of opioid analgesics. Adequate analgesia may be more difficult to achieve when administering opioids to patients on depot buprenorphine. Opioids can be used for analgesia but doses will need to be titrated carefully against clinical response. Consultation with Pain Services or Drug and Alcohol Specialists is recommended.
There are potential drug-drug interactions
There are a number of clinically relevant drug-drug interactions (DDIs) that could occur for patients on depot buprenorphine. Some of these include:
- Interactions with CNS depressants that increase the risk of overdose such as other opioids, alcohol, gabapentinoids, antihistamines, anti-psychotics and benzodiazepines.
- Except in emergency situations, opioid antagonists should generally not be used in patients using depot buprenorphine.
- The metabolism of CYP3A4 inhibitors and inducers, anticholinergics and diuretics may be altered. This includes rifampin, carbamazepine, phenytoin, phenobarbital; macrolide antibiotics such as erythromycin, azole-antifungal agents and antiretroviral medications such as ritonavir.
Depot buprenorphine is released slowly and can have an extended duration of effect
Though depot buprenorphine is administered weekly or monthly, plasma concentrations of buprenorphine slowly reduce after the injection and may remain at levels that cause at least some opioid partial agonist effects for up to 20 weeks in some people, depending on dose and duration of treatment. There may therefore be a persisting though reducing effect on analgesia requirements and DDIs for many weeks after the drug is administered.
How will you know if your patient is on depot buprenorphine?
In the first week after administration of Sublocade™ a small collection may be palpated. Mostly however, neither product is noticeable on external examination. Patients have been encouraged to carry and present a wallet card explaining their depot buprenorphine treatment status. However, patients might be reluctant to disclose that they are on depot buprenorphine due to previous experiences of stigmatisation or discrimination by health workers. Respectfully explaining why you need to know about medications including depot buprenorphine, and maintaining a non-judgemental approach to their drug use, helps improve the accuracy of the history obtained.
When a patient presents who has been receiving depot buprenorphine, clinicians should, as is usual with patients on opioid replacement therapy, confirm last dosing details in order to inform safe treatment. This includes recent dosing history, the date of last dose, the dose received and when the next dose is due.
Can GPs prescribe depot buprenorphine?
GPs cannot yet prescribe depot buprenorphine, even if they are accredited prescribers of opioid agonist medications. The Therapeutic Goods Administration (TGA) has restricted prescription of the product to specialist settings only for the first six months. This will be reviewed in early 2020. Further advice will be distributed when the eligibility criteria are changed, and will be posted on the NSW Health Alcohol and Other Drugs Depot Buprenorphine webpage.
More information and support is available for GPs
The NSW Drug and Alcohol Specialist Advisory Service (DASAS) is a 24/7 helpline that enables health professionals to get advice from specialist alcohol and other drug medical and clinical nurse consultants on any drug and alcohol clinical issues. DASAS clinicians will provide advice on clinical issues related to depot buprenorphine.
Phone DASAS: Sydney metropolitan: (02) 9361 8006; Regional and rural NSW: 1800 023 687