Learning Objectives

• Describe the mediators, receptors and channels involved in nociception, and the neural pathways for ascending transmission and descending inhibition of pain (linked to NEURO)
• Identify the sites of action of analgesic drugs in these processes and pathways
• Describe the cellular mechanisms responsible for the therapeutic effects of NSAIDs
• Describe the main adverse effects of NSAIDs and relate these to their target enzymes
• Describe the proposed mechanisms of action of paracetamol
• Describe the cellular mechanisms of action of opioids in analgesia
• Outline the mechanisms responsible for the major adverse effects of opioids
• Describe the mechanisms of action of tricyclic antidepressants and anticonvulsants in the treatment of neuropathic pain
• Outline the clinical use of analgesic classes in the treatment of nociceptive vs neuropathic pain
• State the mechanism of action of local anaesthetics including the concept of use-dependence
• Explain the effect of pH on the action of local anaesthetics

Descending Pain Inhibitory Pathways

• [PGs] reduce threshold of stimulation of nociceptors, causing?
• what is the role of the periaqueductal gray (PAG) in pain?
• the PAG sends descending projections via [2 areas]?
• how do these pathways inhibit ascending pain signals?

Pharmacological Approach to Pain

• drugs for management of mild acute pain?