3.10.5 Drug Treatment

Within a person's body, a large variety of chemical processes are taking place continually. Someof these processes are involved in breaking down the chemical substances that make up food. Some processes are involved in releasing chemical energy - for example, the reaction that oxidises glucose to release energy for use by muscles in contraction. Other processes construct the chemicals needed to function normally, such as hormones and neurotransmitters. 

Some diabetes result from malfuntions in the body's chemical process.

Drug treatment can help to adjust chemical imbalances.

A drug used for medical purposes is a substance (normally in a pure, refined form) that is administered to the patient in carefully controlled amounts, usually repeatedly and regularly, in order to achieve one or more of the following:

• To make up for a chemical imbalance in the body
• Help the body to fight infectious disease agents
• Relieve or palliate unpleasant symptoms
• Reduce pain. 

A drug typically has three different names. A brand name (given by the pharmaceutical company marketing the drug), a generic name indicating the type (or family) of drug and a chemical name, which gives the chemical composition.

Drugs are sometimes grouped together because they have a similar chemical composition. For example, the drugs known as opioids are derived from opium poppies. One of these is morphine.

Drugs can also be grouped according to the disorder they are designed to treat. Drugs ususally include the name of the disorder (antidepressants). 

Drugs can be grouped together according to the effects they have on the body. The names of these groups usually refer to some physiological process. 

Some drugs are extracted from the tissues of plants or animals and then purified. 

Most drugs are synthesised by routine industrial chemical processes. These include drugs that were originally derived from plants and animals, such as asprin. Synthetis production of drugs is often cheaper and produces a purer and safer product.

Certain drugs are manufactured biologically, using genetically modified life forms. 

Before a new drug can be licensed for use, it must be tested for effectiveness and safety. Initial tests are carried out using animals. If severe adverse effects are produced in these early trials, the drug is unlikely to be tested further. If animal testing reveals no serious problems and the drug has the desired theraputic effect, it can begin clinical trials. 

Following these trials, the drug is assessed by the Comittee on Safety of Medicines. They take into account the benefits and adverse effects of the drug. In some cases, a drug with serious side effects will be approved, provided the benefits minor benefits will only be approved if there are only minor effects.

Once licensed, the drug can be marketed by a pharmaceutical company, usually under a brand name.

Most drugs can only be accessed through a prescription made by a practitioner - usually a GP. 

However, some drugs are available without prescriptions and can be purchased in pharmacies and supermarkets. Most of these drugs are intended to treat aches and pains, inflammation and allergic reactions, rashes, coughs and congestion. These drugs are safe enough not to require a medical supervision. High doses can cause serious harm. Some non-prescription drugs are sold under brand names, however they can be found cheaply with a generic name.

Mouth

• Patient swallows a tablet, capsule or liquid. The drug passes into the intestines, where some of it is absorbed into the bloodstream. This results in the drug being transported to all parts of the body via the blood.

Sprays and inhalers

• Some drugs are inhaled. The patient uses an inhaler, which delivers a fine spray of the drug to the airways and lungs. This is an effective method of targeting drugs to the respitory system. Administration is easy and gives rapid relief of symptoms.

 Suppositories

• Are bullet-shaped blocks of gel that contai drugs. They are inserted into the rectum via the anus. The gel slowly dissolves and the drug is absorbed into the bloodstream. An advantage of this is that it can be administer drugs that would be destroyed by the digestive system if they were swallowed. A disadvantage of this is that some patients find it unpleasant and undignified.

Injection

• Drugs can be injected directly into the body via a needle. Some drugs are injected into the vein and some are injected just under the surface of a layer of fat and others are injected into the muscle.
• IV injections provide a rapid delivery of a drug to the body. This can be important in emergencies. IV administration can also allow continuous delivery at precisely controlled rate when required, in the form of a drip through a needle that remians in position for as long as necessary.
• An advantage of an injection is the ability to deliver the drug quick. Disadvantages include slight discomfort caused by the needle.

Creams:

• Creams can be used to deliver drugs to one particular area. These are sometimes called topical creams. they are particularly useful for treating skin conditions. However, drugs in cream can also be sued to penetrate some distance into tissues below the skin.  

Common adverse effects of drugs include nausea, vomitting, diarrhoea and constiption.

Adverse effects are tolerated in drugs that produce strong positive benefits. 

Adverse effects can also occur when prescription or non-prescription drugs are misused.

Sometimes the effects of a drug on the body can be significantly altered in cases where a person is already taking another drug. The two drugs can interact to produce adverse effects. 

This is why GP's ask patients about any medication they already take, before prescribing drugs. Interactions can also occur between medically refined drugs and herbal remedies.