First of all What is DRUG?
A drug is simply defined as any pharmaceutical or medicinal substance which is used to diagnose, cure, prevent, treat a disease.
PHARMACY is a branch of Medical Science that deals with the detailed study of the History, Manufacturing, Properties, Physiological effects, Administration, Distribution, Metabolism, Absorption, Excretion, Mechanism of action, Dosage and Uses of Pharmaceutical Drugs or Substances.
It also includes collection, identification, purification, isolation, synthesis, standardization and quality control of medicinal substances.
There are so many different branches in Pharmacy study but one of the most important branch is PHARMACOLOGY.
PHARMACOLOGY is derived from two Greek words,
(1)Pharmacon-it means drug And (2)logos-it means discourse in or science
It mainly includes the study of ADME- Administration, Distribution, Metabolism and Excretion along with mechanism of action, adverse reactions and therapeutic uses of drugs.
The main divisions of pharmacology are PHARMACODYNAMICS and PHARMACOKINETICS.
PHARMACODYNAMICS includes the study of biochemical and physiological effects of drugs and their mechanism of action.(Simply What the drug does to the body).
PHARMACOKINETICS includes the study of absorption, distribution, binding/localization/storage, biotransformation and excretion of drugs.(Simply What the body does to the drug).
Some other important aspects of pharmacology are:
MATERIA MEDICA which deals with sources, description and preparation of drugs. It is an old branch of pharmacology.
PHARMACOTHERAPEUTICS which deals with the application of pharmacological information for curing diseases and relieving their symptoms. Selection of proper drug, dosage and duration of treatment are a part of pharmacotherapeutics.
CLINICAL PHARMACOLOGY which is the scientific study of drugs in man. The efficacy and safety of a drug is studied ( both pharmacodynamic and pharmacokinetic investigation) in healthy volunteers and patients.
CHEMOTHERAPY which deals with the effects of drugs on micro-organisms and parasites which occur in a living organism. It also includes the treatment of cancer/malignancy.
TOXICOLOGY which deals with the study of poisonous effects of drugs and other chemicals with emphasis on detection , prevention and treatment of poisoning.