There are natural painkillers in our brain – enkefaliny. They are composed of five amino acid units linked in a short peptide chain. Enkephalins are very effective, morphine-like pain relievers, produced in response to shock. They come from endorphins, longer peptides of approx 80 amino acid units. Endorphins are coming in to help the brain, when the body has to fight severe pain for a long time. Their production is not an immediate process following the onset of pain. That's why we're looking for faster-acting painkillers.
We generally know two types of painkillers. Some act on the site of pain and inhibit the transmission of signals from damaged tissue to the brain. The latter act directly on the brain and cause it, that incoming pain signals are not recorded. Drugs from the second group act on the central nervous system and therefore there is a greater risk of side effects, for example, a deteriorated mood. Some of them are also addictive. The first group of drugs works locally and may also have side effects, but sometimes their advantage is this, that they are not only symptomatic, but they also eliminate the very cause of the pain.
In times of, when chemistry and the pharmaceutical industry were not yet known, the only sources of painkillers were plants. Hippocrates, Greek pioneer of medical science, he resorted to the help of just such means. For example, he recommended an infusion of willow bark to relieve labor pains. As for white willow bark, the advice made some sense - the tree produces salicin, which transforms into salicylic acid when boiled in water, pain reliever. This substance inherited its name from the willow tree, whose systematic name is Salix. Salicylic acid relieves pain, but it can also be its cause, because it irritates the stomach lining, which can even lead to bleeding.
Four pain medications are now widely available: aspirin, paracetamol, kodeina i ibuprofen. Millions of tablets are taken daily, however, depending on the country, preferences regarding a specific specificity change. For example, the British prefer paracetamol-based pills, the second most popular drug is aspirin, lek, which one hundred years ago launched the modern pharmaceutical industry. Aspirin is still the most widely used drug in the United States. Codeine was very popular for a long time, which is still popular, but it is currently only sold in combination with other painkillers (for reasons, which we will introduce later). The newest commonly available pain reliever drug that is slowly gaining popularity is ibuprofen.