Subject of drugs is as old as
disease. Illness has been man’s heritage from the beginning of its existence and search for remedies to combat it is
perhaps equally old. Drug is defined as any substance used for the purpose
of diagnoses, prevention, relief or cure of disease in man or animal.
Pharmacology is defined as a science that deals with the drugs. The world pharmacology is actually derived from the Greek
word “Pharmacon”(an active principle) and logos (a dicose or treatise).
TYPES OF DRUGS
There are various types of drugs
depending on their constituents. There are basically five classifications for drugs.
- Mineral drugs: Liquid Paraffin and Magnesium Sulphate.
- Animal drugs: Insulin, Thyroid extracts, Heparin, Vaccines.
- Plants drugs: Monhin, Digoxin, Quinine, Atropine, Reserpine.
- Synthetic Drugs: Aspirin, Sulphonamide.
- Micro Organism Drugs: Bacteria, fungi, isolated from soil are important
sources of antibiotics. Example, Penicillin.
DRUGS AND PHARMACOLOGY LIFE CYCLE
In the past most drugs have been
discovered either by identifying the active ingredient from traditional remedies or by serendipitous discovery.
A new approach has been to understand how disease and infection are controlled
at the molecular and physiological level and to target specific entities based on this knowledge. The process of drug discovery involves the identification of candidates, synthesis, characterization, screening, and assay for
therapeutic efficacy (Lea)
PROCESS OF PHARMACOLOGY
Dose is defined as amount of drug
to be administered at a time. Therapeutic dose is amount of drug administered
to elicit required clinical effect. Whereas more than therapeutic dose which gives toxic effects is called as toxic dose.
Another important consideration in drug administration is the absorption of
the drug. It is the process by which the drugs are transported from site of administration into the blood. Further passage of drug from blood to the various tissues and body fluids is called as distribution which depends upon plasma protein
Similarly the process by which drugs
are removed from the body, mainly by kidney, by way of filtration, secretion and to some extent through saliva, feces, sweat,
lachrymal fluid and milk is called as excretion of drugs. Both the above,
administration and excretion of drugs forms are important part of Pharmacology (Robertson, 1918).
ADVERSE DRUG REACTIONS TO BE
TAKEN CARE BY PHARMACOLOGY
The various side effects that are taken care by pharmacology are:
- Side effects: adverse effects which occur at therapeutic dose and can not be prevented. These effects are sometimes
useful in some of the diseases and thus may be a desirable point in some specific cases.
- Untoward effects: adverse effects which occur with therapeutic dose and are undesirable.
- Toxic effects: these are seen usually when drugs administered in large
doses (sciencedaily2007 [online]).
CHALLENGES FOR DRUGS AND PHARMACOLOGY
Despite advances in technology and understanding of biological systems, drug discovery is still a long process with low rate of new therapeutic discovery.
Information on the human genome, its sequence and what it encodes has been hailed as a potential windfall for drug discovery, promising to virtually eliminate the bottleneck in therapeutic targets that has been one limiting
factor on the rate of therapeutic discovery (sciencedaily2007 [online]).
Drugs and Pharmacology by Arthur Robertson (1918)
Pharmacology by Lea
URL http:// www.sciencedaily.com[online source]. Last
accessed 5 November 2007