Pharmacology

Pharmacology may be defined most simply as the study of drugs. In the broadest sense it includes all the scientific knowledge of drugs, such as the name, source, physical and chemical properties, and the mixing or preparing of drugs in the form of medicine. It is concerned also with physiolo­gical actions of drugs - their absorption, action, and fate in the body - and with their therapeutic uses, as well as the poisonous effects that result from over dosage.

A drug is a chemical substance that affects living protoplasm and does not act as a food. It is used in the cure, tre­atment, or prevention of disease in man or animals. In ad­dition, drugs alleviate suffering and pain.

The subject of pharmacology may be divided into a number of distinct sciences such as pharmacognosy, pharmacy, posology, toxicology, pharmacodynamics, and pharmacotherapeutics.

Pharmacognosy is a descriptive science and is concerned with the recognition, quality, purity by macroscopic and micro­scopic means, and identification of plants and animal drugs.

Pharmacy deals with the preparation, stability, preser­vation, and storage of drugs. From these drugs the pharma­cist prepares compounds, and dispenses medicines. Most drugs are prepared by pharmaceutical manufacturers and are di­stributed to the pharmacy or hospital in such suitable dosage forms as tablets, capsules, liquid

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preparations, or sterile solutions for injection. The

pharmacist now has no less a responsible role in properly dispensing the preparations in finished forms than when he powdered, dissolved, mixed, and otherwise compounded prescriptions. He stiff performs these functions for many of these orders.

Posology is concerned with the dosage or amount of a drug given in the treatment of disease. There is a minimum, maximum, usual or therapeutic, and toxic dose for each drug. The most important is the usual dose, which is the oral dose for an adult weighing 70 kg. There are a number of conditions thai modify the dose of a drug.

Pharmacodynamics is concerned with the response of Jiving tissues to chemical stimuli, that is, the action of drugs on the living organism in the absence of disease. It is one of the newest biological sciences and is closely associated with physiology, biochemistry, pathology, and microbiology. It is unique in that its interest is focused on drugs. It is a study of the absorption, fate, excretion, and action of a fo­reign substance in the body.

Purpose of Pharmacology

The purpose of pharmacology as a pure science is to de­termine the response of living tissues to chemical stimuli, chiefly drugs or prospective drugs on living tissues of the body in the absence of disease, as, for example, in inducing sleep or exciting to retard sleep. It also attempts to correlate chemical structure with response and to classify chemically related drugs into groups such as the

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barbiturates and the sulfonamides.

As an applied or practical science, it has the following functions: 1) to test drugs quantitatively and standardize them so that they are available to the doctor and patient in a uniform and dependable form; 2) to determine how drugs produce their effects on the animal body, and 3) to develop new drugs.

Answer the following questions:

1 What is Pharmacology? 2 What is the definition of Pharmacology as a science? 3 Is Pharmacology concerned with therapeutic use of drugs? 4 What do drugs affect? 5 What are the drugs used in? 6 What branches of Pharmacology do you know? 7 What is the purpose of Pharmacognosy? 8 What does Pharmacy deal with? 9 Who pre­pares medicines? 10 Who is responsible in properly dispen­sing of medicines? 11 What is the scope of Posology? 12 What may the overdosage of drugs cause? 13 How do you understand the words "usual dose"? 14 What does Pharmacodynamics deal with? 15 What is the purpose of Pharmacology as an applied science? 16 What are the functions of Pharmacology as a pure science?

Supplementary reading. Drugs Used as Medicines

There are two kinds of drugs used as medicines. One

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kind is called over-the-counter drugs. An over-the-counter (OTC) drug is a drug that can be bought without a doctor's written order.

OTC drugs can help people who have mild health problems. OTC drugs can help stop a cough or relieve a headache. However, OTC drugs can be harmful. Harm may result if they are not used correctly. The labels on these drug containers give important information. They tell how much of the drug to take. They tell how often the drug is to be used.

Over-the-counter drug labels also have warnings. A warning is a statement telling you that the drug may not be right for you. It tells when you should not take the drug. A warning may tell you to contact a doctor if an illness continues for a long time.

The second kind of drug used as medicine is a prescription drug. A prescription drug is a drug ordered in writing by a doctor. The doctor writes the prescription for one specific person. The kind of health problem that needs treatment must be considered. The doctor must also consider the person's weight and height. A drug that is right for one person may not be right for another.

OTS and prescription drugs can cause side effects. A side effect is an unwanted body change caused by a drug. A headache or an upset stomach are examples of side effects. Medicine labels have warnings about possible side effects. Stop taking any medicine if you have a side effect. Ask the doctor who ordered the drug. The doctor may then prescribe a different kind of drug.

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