Hi, thanks for asking in Healthcare Magic. RSD (Reflux Sympathetic Discharge) or Complex Regional Pain Syndrome presents as severe burning pain with signs of inflammation like increase in temperature, redness, edema (swelling) and excessive sweating all indicating excessive sympathetic stimulation. It is more common in patients with multiple sclerosis, spinal cord injury and those who have suffered stroke. Many modalities of treatment are available. Some of them are 1. Regional Nerve Block with local anesthetics like Lignocaine. 2. Bier block (Regional intravenous sympatholytic drugs) with Phenoxybenzamine. 3. Intrathecal Baclofen. 4. Corticosteroids/ Calcitonin Ketamine belongs to the hallucinogen Phencyclidine group. It is an anesthetic. It causes dissociative anesthesia ie., feeling of dissociation from ones own body and surroundings along with analgesia and amnesia. Although still not yet completely proved, Ketamine therapy is also advocated in RSD. It needs to be given only by experts. While low dose subanesthesia with Ketamine is found to benifit some, medically induced coma with Ketamine is banned in many countries. Ketamine is dangerous in patients with high BP, increased intracranial pressure and with heart problems. RSD due to stoke could be due to high BP and such patients should not be given Ketamine. I hope this is useful to you.