NSAIDs, Paracetamol, Anticonvulsants, Antidepressants and Ketamine

NSAIDs work well in acute pain and as part of an opioid-sparing multimodal approach, but they carry gut, cardiac and renal risks and are likely less effective when chronic pain is driven by nervous system changes. Paracetamol has a low side effect profile within its daily limit and an uncertain mechanism. Anticonvulsants such as pregabalin, gabapentin and carbamazepine act as nerve stabilizers for neuropathic pain, are often trialed one after another, and can cause cognitive blunting, dizziness and sedation. Low-dose tricyclics such as amitriptyline (around 10 to 50 mg, against 70 to 100 mg for depression) help neuropathic pain within days and can improve sleep. SNRIs such as duloxetine and venlafaxine suit widespread pain and fatigue, and Alison explains how stigma and side effects affect adherence. Ketamine infusions of 4 to 14 days can give some patients, for example with CRPS, relief for up to three months, while others find the experience overwhelming.