Analgesics: Nursing pharmacology

Analgesics, also commonly known as painkillers, are medications primarily used to relieve pain, such as a headache, muscle and neuropathic pain, as well as pain related to trauma and fractures.

Analgesics can be subdivided into two main groups: non-opioid analgesics, and opioid analgesics. Keep in mind though that there are a number of other medications that primarily serve other purposes, but can be used as analgesics.

These medications include antidepressants like amitriptyline, anticonvulsants like gabapentin, and corticosteroids like dexamethasone, as well as local anesthetics like lidocaine.

Now, let’s start with non-opioid analgesics, which include non-steroidal anti-inflammatory drugs or NSAIDs, and acetaminophen. NSAIDs inhibit the enzyme cyclooxygenase or COX, both in the central nervous system and peripheral tissues.

Now, there are two types of COX enzymes. The first one is called COX-1, which is indirectly involved in platelet aggregation, production of protective mucus in the stomach and vasodilation of the renal vasculature.

On the flip side, COX-2 is only active in inflammatory cells and vascular endothelium during inflammation, and is involved in the production of small pro-inflammatory compounds like prostaglandins.

Now, a very commonly used NSAID is acetylsalicylic acid, often referred to as aspirin, which is taken orally. On the other hand, non-aspirin NSAIDs can be further classified as non-selective COX inhibitors that act on both COX-1 and COX-2, like ibuprofen, naproxen and ketorolac; and selective COX-2 inhibitors, like celecoxib.