Bios275 Application Paper

Application Paper 2

Pain Medication

An analgesic, or painkiller, is any member of the group of drugs used to achieve analgesia — relief from pain. The word analgesic derives from Greek ἀν-, "without", and ἄλγος, "pain".

Analgesic drugs act in various ways on the peripheral and central nervous systems. They are distinct from anesthetics, which reversibly eliminate sensation, and include paracetamol, the non-steroidal anti-inflammatory drugs such as the salicylates, and opioid drugs such as morphine and oxycodone. In choosing analgesics, the severity and response to other medication determines the choice of agent; the World Health Organization pain ladder specifies mild analgesics as its first step. Analgesic choice is also determined by the type of pain: For neuropathic pain, traditional analgesics are less effective, and there is often benefit from classes of drugs that are not normally considered analgesics, such as tricyclic antidepressants and anticonvulsants.

Paracetamol and NSAIDs

The exact mechanism of action of paracetamol/acetaminophen is uncertain but appears to act centrally in the brain rather than peripherally in nerve endings (MMOML). Aspirin and the other non-steroidal anti-inflammatory drugs inhibit cyclooxygenases, leading to a decrease in prostaglandin production. In contrast to paracetamol and the opioids, this reduces not only pain but inflammation as well. Paracetamol has few side-effects and is regarded as generally safe, although excess or sustained use can lead to potentially life-threatening liver damage and occasionally kidney damage. While paracetamol is usually taken orally or rectally, an intravenous preparation introduced in 2002 has been shown to improve pain relief and reduce opioid consumption in the perioperative setting. NSAIDs predispose to peptic ulcers, renal failure, allergic reactions, and occasionally hearing loss, and they can increase the risk of hemorrhage by affecting platelet function. The use of aspirin in children...