Chemistry and How Opiates Work
People have forever known that feeling good can reduce pain. This in fact is the effect of endorphins. The brain has receptors which endorphins can attach themselves to, when they do this creates the feeling of elation and happiness also relieving pain.

Similarly scientists and doctors have for a long time known that opiates reduce the effect of pain but it was only in the early 70's that they discovered a direct connection between opiates and the similarity they bind to the brain receptors like endorphins.

Opiates are biochemical substances that are extracted from opium; a substance which is found in the Papaver Somniferum plant known as the Poppy and several other variants. Opium yields many natural medical substances such as Morphine, Codeine and others. These can be produced into soluble salts such as Morphine Sulfate and Codeine Phosphate which are used directly for medical use such as in tablets.

Morphine and Codeine are absorbed into the body in different ways. Morphine is converted to the brain through the digestive system whereby a large quantity of it is destroyed before it reaches the brain. Codeine on the other hand is converted to the brain through the gastrointestinal tract where a large part of it is converted into the brain. Nevertheless even when considering this fact Morphine is still more potent for fighting pain than Codeine, the importance of this conversion process lies in the fact that Codeine does not cause any damage to the digestive tract over prolonged use. For this reason Codeine is preferred as an effective and safe pain relief agent.

Scientists discovered in the seventies that Morphine attaches itself to brain receptors very similarly to endorphins producing the same effects of euphoria and pain relief.

In pill form Codeine is usually combined with other pain relief agents such as NSAIDs. It was discovered that when combined with Tylenol, Aspirin, Panadol, Caffeine, Ibuprofen, Codeine was twice as effective in fighting pain due to the peripheral effects of the second pain relief agent. This meant that a patient could take half as much codeine as necessary to relieve pain.

This peripheral action of other pain relief agents is quite important because it delays the effect of tolerance when using opiates. A patient who takes large doses of Codeine will eventually build up tolerance over prolonged use. Therefore he would have to take larger doses in the future for the same pain relief effects; the patient's body gets used to the opiate medication. However with a non tolerance type peripheral agent like Tylenol, Aspirin, Panadol etc. used in combination with an opiate like codeine the onset of tolerance is severely delayed and the effectiveness of the codeine in fighting pain is doubled.