Analgesic

From the Greek anti (against) and algos (pain), as their name indicates analgesics are medicines intended to relieve pain.

How do analgesics work ?

In 1986, the World Health Organisation (WHO) set up a pain management protocol defined according to 3 different steps, en depending on the severity of the pain, which was defined as mild, moderate or severe:

• peripheral analgesics have a local effect on pain. This is the case for aspirin or paracetamol. It is the first step for mild to moderate pain;
• step 2 analgesics are recommended for moderate to severe pain if step 1 analgesics fail. These act on the central nervous system;
• Step 3 is the group of medicinal products produced from morphine and its derivatives. While these compounds have the same mechanism of action as step 2 analgesics, they are more potent. They are indicated for use in the treatment of severe pain or if step 2 analgesics have failed.

Analgesics may be taken orally, rectally or locally (creams for application). They may also be administered via intra-muscular or intravenous injection, and sometimes through infusion pumps for the most potent analgesics.

Sources:

• Merck Manual – 4^th ;
• Principles of Internal Medicine, TR Harrison, Ed. Flammarion; National Institute for Cancer, consulted on 27 May 2011.