A 3-step algorithm for the management of acute and chronic pain that recommends giving nonopioid analgesics only for mild pain (step 1); nonopioid analgesics and mild opioids in moderate pain (step 2); and nonopioid analgesics, mild opioids, and strong opioids in severe pain (step 3). A modification of the WHO analgesic algorithm recommends interventional procedures (e.g., nerve blocks) for unrelenting pain (step 4).