BACKGROUND: Opioids are good painkillers, but many patients treated with opioids as painkillers developed a secondary addiction. These patients need to stop misusing opioids, but the mild-to-severe clinical symptoms associated with opioid withdrawal risk increasing their existing pain. In such cases, ketamine, which is used by anaesthetists and pain physicians to reduce opioid medication, may be an effective agent for managing opioid withdrawal. CASE PRESENTATION: We describe the case of a woman who developed a severe secondary addiction to opioids in the context of lombo-sciatic pain. She presented a severe opioid addiction, and her physicians refused to prescribe such high doses of opioid treatment (oxycontin® extended-release 120 mg daily, oxycodone 60 mg daily, and acetaminophen/codeine 300 mg/25 mg 6 times per day). To assist her with her opioid withdrawal which risked increasing her existing pain, she received 1 mg/kg ketamine oral solution, and two days after ketamine initiation her opioid treatment was gradually reduced. The patient dramatically reduced the dosage of opioid painkillers and ketamine was withdrawn without any withdrawal symptoms. CONCLUSION: Ketamine displays many interesting qualities for dealing with all symptoms relating to opioid withdrawal. Accordingly, it could be used instead of many psychotropic treatments, which interact with each other, to help with opioid withdrawal. However, the literature describes addiction to ketamine. All in all, although potentially addictive, ketamine could be a good candidate for the pharmacological management of opioid withdrawal.