D1.+Pharmaceutical+products

The body has its own natural healing processes that usually overcome tissue damage and infections by microbes, though sometimes medicines and drugs may be required. A medicines or drug is any chemical that does one or more of the following:
 * D.1.1**
 * Alters the physiological state, including consciousness, activity level or coordination
 * Alters incoming sensory sensations
 * Alters mood or emotions

Morphine was extracted from the poppy Papaver somniferum early in the nineteenth century and later salicylic acid, the precursor of aspirin, was isolated from willow bark. Melatonin, a substance produced by the pineal gland in humans, is known to bring on the onset of sleep and is often taken by people suffering from 'jet-lag'. It is classed as food in America but as a drug in Europe because of its potential to modify physiological functions in humans. Medicines are commonly used to improve health, by assisting the body in its natural healing process. The mechanism of drug action is not yet figured out as the body can be 'fooled' into healing itself through the 'placebo' effect.The placebo effect is the well established fact that administration of inactive substances, instead of active drugs, still leads to a reported improvement in the condition.

A new product is usually isolated from an existing species or synthesised chemically and then subjected to intense lab testing. First the new product is tested on animals, usually rabbit and mice because they share the most DNA with humans, to determine the lethal dose (LD50) required to kill 50% of the animal population. Then the effective dose (ED50), the dose required to bring about a noticable effect in 50% of the animal population, is found. The LD50 and ED50 are then used to __#|find__ the therapeutic index. After the therapeutic index has been found the new product is able to undergoes initial clinical trials in the form of a double blind test where neither the researchers or the volunteers know who recieved the placebo. Both the risk-to-benefit ratio of side affects and the tolerance (how a body adapts to the drug over time) are also determined. The product will continue to undergoes rigorious tests until the FDA deems it acceptable to sell. A case of where this can go wrong is Thalidomide where a drug used to combat morning sickness resulted in a high percentage of the women having children with small or missing limbs.
 * D.1.2 - Research, Development and Testing of __#|New__ Products**

The therapeutic window is a measure of the relative margin of safety of a drug. It is the ratio of the lethal dose (LD50) to the therapeutic dose of the drug (ED50 - the dose required for the drug to have a noticeable effect on half the population).

Therapeutic window = __LD50__ ED50

In order to reach the site where the drug is needed it must be absorbed into the bloodstream. The method in which the drug is administered determines the route taken by the drug and the speed at which it is absorbed into the bloodstream. The four main methods in which a drug can be administered are oral, inhalation, rectal, and parenteral (injection) There are three different methods of injection, -Intramuscular, usually injected into the arm, leg, or buttock muscles - Subcutaneous, injected directly under the skin - Intravenous, this has the most rapid effect because the drug enters the bloodstream directly
 * D.1.3- Methods of Administering Drugs**


 * D.1.4 Discuss the terms therapeutic window, tolerance and side-effects.**

Therapeutic Window= LD50/ED50

The therapeutic window is a measure of the relative margin of safety of a drug. It is the ratio of the lethal dose (LD50) to the therapeutic dose of the drug (ED50 - the dose required for the drug to have a noticeable effect on half the population).

Tolerance occurs as the body adapts to the action of the drug. People taking the drug need increasing doses to achieve and effect. The danger is that increasing the dose will increase the risk of dependence or side effects. If the drug passes the initial clinical trial, it will go through further phases where its use is widened. If it passes all tests it will be classified (varying by country) as an OTC (over the counter) or a drug only to be administered by a doctor.

Side effects are unwanted effects such as bleeding in the stomach caused by aspirin and constipation due to morphine. Risk to benefit ratios must be used to decide if the possible side effects of the drug are outweighed by its benefits.