In Australia, high-dose sublingual buprenorphine and long-acting injectable buprenorphine are available. High-dose buprenorphine is used predominantly in the setting of opioid use disorder and has a role in chronic pain. Palliative care specialists are increasingly involved in pain management and end-of-life care for patients on these medications, yet there is a lack of education and training about high-dose buprenorphine for palliative care specialists. We describe our experience caring for John (fictional name), a gentleman with chronic pain and a new high-grade post-transplant lymphoproliferative disorder prescribed high-dose buprenorphine. We share the challenges and experience in caring for John as he deteriorated into the terminal phase and died of his illness. We include potential management options and the rationale for our decision to rotate John from high-dose sublingual buprenorphine to subcutaneous oxycodone. We conclude with practice implications and suggestions for improved patient care and clinician experience, including increased collaboration between palliative medicine, acute pain, and addiction medicine services, increased education and training for palliative care specialists about high-dose buprenorphine, and ultimately the development of consensus high-dose buprenorphine to oral morphine equivalence guidelines.