Pain Management and Analgesic Ladder

Study Notes

The analgesic ladder involves progressing from NSAIDs or acetaminophen to less potent opioids like hydrocodone, codeine, or tramadol, then to potent opioids like morphine or oxycodone for severe pain.

Inflammatory pain originates from infection or inflammation.
Neuropathic pain is complex and results from nerve system injury.
Nociceptive pain is further categorized into cutaneous pain, somatic pain, and visceral pain.

Amitriptyline is used to treat moderate to severe chronic pain.
Triptans are used in the treatment of migraines.
NSAIDs and acetaminophen are widely used for mild to moderate pain and reducing fever.

Most clinically used opioid drugs bind to mu-opioid receptors, producing effects such as analgesia, respiratory depression, and euphoria.
Enkephalins are endogenous opioid peptides found as a mixture of peptides differing in their terminal amino acids.
Enkephalins have a transient action due to rapid degradation by amino peptidases.

Morphine is a prototype ligand for mu-opioid receptors and is obtained from plants.
Codeine is obtained from the methylation of morphine and has analgesic effects due to its conversion to morphine via O-demethylation.
Heroin is a synthetic derivative of morphine with rapid metabolism to morphine, leading to euphoric effects.
Hydromorphone is more potent than morphine and is marketed as an analgesic agent.
Hydrocodone is an antitussive agent often combined with acetaminophen or aspirin for pain treatment.
Oxycodone is a beta-hydroxyl version of hydrocodone and is marketed in combination with acetaminophen/aspirin/ibuprofen.