There remains uncertainty regarding the existence, mechanism and frequency of opioid-induced hyperalgesia (OIH). Literature to date has been dominated by the phenanthrene opioids, fentanyl and remifentanil. This case draws attention to alfentanil as an additional contributor. In this report, suspected OIH and subsequent reduction in opioid dose led to a dramatic diminution of pain. Omission of such a differential may have led to detrimental consequences. Underlying dementia heightened his vulnerability and illustrates the necessity of clinical expertise in the diagnosis and management of OIH, particularly when diagnostic criteria are lacking. The case demonstrates the need to include OIH as a plausible differential diagnosis in escalating pain where opioid tolerance, disease progression and non-opioid sensitive pain are excluded.