Intro to the Principles of Pharmacology

Question 1

Pharmacology

Answer 1

is the science basic to medicine that is about the effects of chemicals on living systems at all levels of organization (molecular to the whole body). The chemicals may be drugs used to prevent, diagnose or treat disease. Drugs modify physiological processes-they do not create new processes or effects. The relationship between the dose of a drug given to a patient and the utility of that drug in treating that patient’s disease is described by a drug’s pharmacokinetics and pharmacodynamics.

Question 2

Pharmacokinetics

Answer 2

deals with the absorption, distribution, biotransformation and excretion of drugs. Pharmacokinetics is thought of as the body having actions on the drug whereas pharmacodynamics is thought of the drug having effects on the body

Question 3

Pharmacodynamics

Answer 3

Pharmacodynamics deals with the study of the biochemical and physiological effects of drugs and their mechanisms of action. Pharmacokinetics is thought of as the body having actions on the drug whereas pharmacodynamics is thought of the drug having effects on the body

Question 4

Pharmacotherapeutics

Answer 4

is the use of drugs in the prevention and treatment of disease. Many drugs stimulate or depress biochemical or physiological function in human beings in a sufficiently reproducible manner to provide relief of symptoms or, ideally, to alter favorably the course of disease. Conversely, chemotherapeutic agents are useful in therapy because they have minimal effects on human beings but can destroy or eliminate pathogenic cells and organisms.What is important to remember is that virtually all drugs result in more than one effect. In general, one effect predominates over a particular dose range, i.e., the therapeutic window and, within this dose range the drug may be termed selective. If a drug resulted in one and only one effect the drug would be termed specific. It is the goal of pharmacotherapeutics to achieve specificity, however is most often unachievable. Toxicity may result if the dose range is exceeded. It has often been emphasized that there is only a quantitative difference between a drug and a poison.

Question 5

Toxicology

Answer 5

Toxicology is an aspect of pharmacology that deals with the adverse effects of drugs and chemicals.

Question 6

Therapeutic Index

Answer 6

is a relative measure of dose that a drug can achieve a therapeutic effect without producing a side effect, calculated as the ratio of the TD50 (toxic dose) to the ED50 (effective dose) for the desired effect. Therapeutic index of less than 1 would suggest that the drug will have side effects and could produce toxicity in patients at doses that are needed to produce the therapeutic effect. The safest and most desirable drugs are drugs with a large therapeutic index, particularly if the side effect is a serious one. Most if not all drugs come with side effects resulting in undesirable biological effects. Therefore, it is always important to inform patients that drugs produce more than one effect.

Question 7

Define what it takes for a drug to have affinity for a receptor.

Answer 7

The onset, intensity and duration of responses to chemicals are determined by factors that govern chemical concentration at the site of action. In addition, in the great majority of cases, the drug molecule interacts with a selective molecule in the biological system that plays a regulatory role, i.e., a receptor molecule. In order for a drug to interact with its receptor, a drug molecule must have the appropriate size, electrical charge, shape and atomic composition. A drug’s “attractiveness” to a receptor is referred to as affinity (figure 1). A drug must also have the necessary properties to be transported from its site of administration to its site of action (KADME). Kinetics, Absorption, Distribution, Metabolism and Excretion examines the properties of chemicals and characteristics of biologic processes that influence tissue concentration of drugs and toxins.