HOW DO PAINKILLERS WORK ?

All painkillers work by interfering with the pain-transmission process.Although there are many different types, painkillers-or analgesics-usually relieve pain in one of two ways:

·        By predominantly reducing inflammation or

·        By predominantly affecting the central nervous system.

PAIN KILLERS THAT ACT BY REDUCING INFLAMMATION

Inflammation is the body’s way of responding to injury, infection or invasion by foreign bodies. Inflammation is controlled by inflammatory mediators, substances that are made by the body and which may make inflammation worse by sensitizing pain receptors.Drugs like aspirin and ibuprofen are called non-steroidal anti-inflammatory drugs (NSAIDs). 

As their name suggests, they work by preventing or limiting inflammation-specifically by blocking the manufacture of prostaglandins. Although prostaglandians do not cause pain themselves, they sensitize nociceptive nerve endings to other inflammatory mediators (like bradykinin and histamine) and thereby amplify the basic pain message. Prostaglandins are manufactured in the body by an enzyme called cyclo-oxygenase, or COX for short. 

The COX enzyme helps to metabolise (or breakdown) a larger substance called arachidonic acid, into pain-causing prostaglandins. By attacking COX and stopping it from doing its job properly, aspirin-like drugs slow down the production of the pain-causing prostagladins. However,slowing down COX is not always a good thing. Confusingly, there are two forms of the COX enzyme- COX-1 and COX-2. Blocking COX-2 ultimately helps to relieve pain. But, most NSAIDs block COX-1 as well, which disrupts other biological processes that are far removed from pain transmission. One of these processes is the production of protective mucus in the stomach. This explains why some people develop gastric ulcers, indigestion and general nausea after taking NSAIDs.

WHEN PAIN ‘GETS ON OUR NERVES

Pain becomes a problem to us when it affects the way in which we live our

lives (i.e. becomes chronic). For example, if we injure our backs or are suffering from a disease like arthritis, we can experience pain that is persistent. But when does pain become ‘a pain’? 

When our pain machinery becomes sensitized and is activated when it shouldn’t be. Pain can be triggered by the irritation of nerve endings (one cause of which is inflammation) or by damage to the nerves.

Pain is generally divided into three types:

·        Acute nocicpetive pain usually originates from the site of injury.

·        Inflammatory pain involves the activation of the immune system.

·        Neuropathic pain is usually caused by damage to the peripheral or central nervous systems.

Type of pain

1.      Acute nociceptive Cause- injury to muscle, soft tissue, bones, joints or skin.  

How it feels-sharp, stabbing, aching, throbbing, can be excruciating but is not usually long lasting.Example-twisted ankle, bee sting, childbirth.

2.      Inflammatory Cause- generation of inflammatory mediators following a painful stimulus.

 How it feels- burning, dull ache, can be excruciating, can come and go, or be virtually permanent.Examples-rheumatoid arthritis.

 3.      Neuropathic Cause- damage to nerve tissue. 

How it feels- aching, tingling, numbness. Can be excruciating, can come and go, or be virtually permanent.Examples- trapped or compressed nerve, nerve damage caused by diabetes.