Important Definition of Pharmacology

Drug: Drugs are any substance other than food which acts on the living body to modify the function of cell, are used for the prevention, diagnosis & treatment of diseases in human beings or other animals.

Medicine: A medicine is a preparation containing one or more drugs mixed in a suitable dosage form in a proper container with a label.

Example of medicine: Ranitidine for treatment of peptic ulcer diseases. Metronidazole for the treatment of amoebic dysentery.

O.T.C Drug (Over the counter drug): Drugs that can be used or supplied without prescription are called O.T.C drug.

Excepients- Substances that are added to medicine to permit to be formed into the proper shape & consistency are called excipients.

Solution – Liquid dosage form where two liquid are completely mixed with each other but does not contain any sugar.

Syrup – It is a concentrated solution of sugar.

Suspension – Liquid dosage form where finely divided solid dispersed in another liquid. In suspension, solid particles are deposited if it remains without agitation.

PFS- PFS is dry powder to produce suspension during use

Dose: Amount of drug or medicinal preparation to be administered at one time is called dose.

Dosage: Determination of the amount, frequency & number of doses of drug for a patient is called dosage.

Therapeutic dose: Dose Required to produce the optimal therapeutic effect is called Therapeutic dode.

Bioavailability: The rate & extent to which active drug enters into general circulation, & subsequently at the site of action is called bioavailability.

or

Svailability of active drugs in the blood is called bioavailability

Potency of a drug: Amount of drug required to produce a therapeutic response, is called potency of a drug

Efficacy of a drug: Ability of a drug to produce a therapeutic response, is called Efficacy of a drug

Falf Life: Time taken by a drug to be reduced by half of its original amount is called half life of that drug.

Importance: Half life determines the dosage frequency of a drug

Elimination Half-life – It is the time required for a given urine concentration of drug to decrease into half of its original concentration.

Receptor: Receptors are macromecular protein structure located at the surface of cell membrane or inside the cell & to which drugs bind to produce a pharmacological effect.

Protein binding: Binding of a drug with plasma protein is called protein biding of that drug.

Importance: More the protein binding prolonged the duration of action of a drug.

Plasma Concentration – Plasma Concentration is the amount of drug per unit volume of blood.

Peak Plasma Concentration – Peal plasma Concentration is the maximum amount of drug per unit volume of blood.