Painkillers

Painkillers

An analgesic, commonly known as a painkiller, refers to any substance within the group of drugs employed to alleviate pain and achieve analgesia. The term "analgesic" originates from the Greek words an- ("without") and algos ("pain").

These drugs exert their effects through various mechanisms on both the peripheral and central nervous systems. They encompass paracetamol (also called acetaminophen in the US), non-steroidal anti-inflammatory drugs (NSAIDs) like salicylates, and opioid medications such as morphine and opium. It's important to distinguish analgesics from anesthetics, which temporarily eliminate sensation.

When selecting analgesics, the severity of pain and response to other medications dictate the choice of agent. The WHO pain ladder, initially designed for cancer-related pain, is widely employed to identify suitable drugs in a stepwise manner. Additionally, the type of pain influences the analgesic choice; for neuropathic pain, conventional analgesics may be less effective, and alternative drug classes like tricyclic antidepressants and anticonvulsants may offer benefits.

The precise mechanism of action of paracetamol/acetaminophen remains uncertain, but evidence suggests it primarily acts centrally rather than peripherally (in the brain rather than nerve endings). On the other hand, aspirin and other NSAIDs inhibit cyclooxygenases, leading to reduced prostaglandin production, thereby alleviating both pain and inflammation (unlike paracetamol and opioids).

While paracetamol is generally considered safe with minimal side effects, exceeding the recommended dosage can cause severe and potentially life-threatening liver damage, and occasionally kidney damage. NSAIDs may increase the risk of peptic ulcers, renal failure, allergic reactions, and in some cases, hearing loss, and they can impact platelet function, raising the risk of hemorrhage. Notably, the use of aspirin in children under 16 during viral illnesses has been associated with Reye's syndrome, a rare but serious liver disorder.