At the beginning, the WHO was developed to use in cancer pain. For chronic pain due to other causes, the WHO approach should be equally appropriate. The appropriate approach standard is that, following good pain assessment and thorough knowledge of a small number of analgesics. A simple approach should produce pain relief in the majority of patients. In essence, the approach combines two modalities of pain relief which is the combination of Non-opioid and Opioids analgesics.Non-opioid analgesics, such as NSAIDs or Tylenol, reduce inflammation and/or prostaglandin synthesis and thereby reduce nociceptive stimuli. Opioids reduce nociceptive transmission through inhibition at opioid receptors in the brainstem, spinal cord and perhaps peripheral
