General of Pharmacology

Pharmacology

Definition of Pharmacology

Pharmacology deals with the interaction of drug or exogenously administered chemical molecules with living system.

In simple word – Study of interaction of drug with living body called pharmacology.

Pharmacology is broad field which is divided into mainly two branches-

1. Pharma-co-kinetics.
2. Pharma-co-dynamics .

Pharmacokinetics 

(Pharma means drug and kinetic means movement) 

“What the body does to the drug”.

In pharmacokinetics we investigate the movement of the drug in and alteration of the drug by the body. Basically in pharmacokinetics we study the absorption distribution metabolism and excretion of the drug. 

Example – 

• In example we give pharmacokinetic of paracetamol -
• Paracetamol is rapidly and almost completely absorbed orally. 
• Paracetamol is attaining peak blood levels at 30-60min.
• 25% of paracetamol bound to plasma proteins.
• Paracetamol widely and almost uniformly distributed in the body.
• Paracetamol extensively metabolized in the liver. 
• Paracetamol is excreted in urine.
• Half life of Paracetamol is about 2 to 3 hours.
• Clearance value of Paracetamol is about 5ml/kg/min.  

Pharmacodynamics

(Pharma means drug and dynamic means power).

“What the drug does to the body”.

In pharmacodynamics includes biochemical and physiological effect of drugs & mechanism of action. 

Mechanism of action of drug at organ/tissue/cell/macromolecular levels.

Example-

Pharma-co-dynamics

Scope of Pharmacology

Pharmacy 

Pharmacy includes collections, identification, purification, isolation, synthesis, standardization and quality control of medicinal substances.

Pharmacokinetics 

It deals with the rates of absorption, distribution, metabolism & excretion of drug. It also deals with drug concentration in body fluids & tissues.

Pharmacodynamics    

Study of the biochemical & physiology effect of drugs on the body and their mechanism of action.

Clinical Pharmacology

It is the scientific study of drug (both old and new drugs) in human being.

It includes pharmacodynamics and pharmacokinetics investigation in healthy volunteers and in patients / safety of drug / evaluation of efficacy / comparative trials with other forms of treatment / surveillance of patterns of drugs use / adverse effect / dose / toxic effect / duration of treatment etc.

The aim of clinical pharmacology is to generate and collect data for optimum use of drugs and the practice of evidence based medicine.

Toxicology 

It is the study of poisonous effect of drugs and other chemical (environmental pollutant, industrial, agricultural, household, homicidal) with emphasis on detection, prevention and treatment of poisonings. It also includes the study of adverse effect of drugs. 

Chemotherapy 

It is the treatment of systemic infection or malignancy with specific drug that have selective toxicity for the infecting organism/malignant cell with no or minimal effect on the host cells.

Pharmacotherapeutics  

Selection of the most appropriate drug, dosage and duration of treatment taking into account the specific features of a patient are a part of pharmacotherapeutics.  

It is the application of pharmacological information together with knowledge of the disease for its prevention mitigation or cure.  

Pharmacovigilance (PV or PhV)

Pharmacovigilance is includes collection, detection, assessment, monitoring and prevention of adverse effect with pharmaceutical products. Pharmacovigilance is also known as drug safety.