Principles Pharmacology

Question 1

Pharmacodynamics

Answer 1

What a drug does to the body.

Question 2

Pharmacokinetics

Answer 2

What the body does to a drug.

Question 3

Drug

Answer 3

Any synthetic, or natural, substance of known structure used in the treatment, prevention, or diagnosis of disease.

Question 4

Medicine

Answer 4

A chemical preparation containing one, or more, drugs used with the intention of causing a therapeutic effect.

Question 5

Agonists

Answer 5

Drugs that bind to a receptor to produce a cellular response.

Question 6

Antagonists

Answer 6

Drugs that block the actions of an agonist by binding to the same receptor.

Question 7

Affinity

Answer 7

Is the strength of association between the ligand and the receptor.

Question 8

Efficacy

Answer 8

Is the ability of an agonist to produce a cellular response.

Question 9

EC50

Answer 9

Is the concentration of a drug that produces 50% of the maximal effect. This tells us how potent the drug is.

Question 10

LD50

Answer 10

The concentration of a drug that produces a lethal dose in 50% of the population.

Question 11

Basal Activity

Answer 11

is the receptor activity that occurs even when there is no agonist around.

Question 12

Inverse Agonist

Answer 12

Simply eliminates basal activity (binds to receptors and stabilises them).

Question 13

Competitive Antagonism

Answer 13

When we have both agonist and antagonist and they bind to the same site on the receptor, they will compete for that side.

Question 14

Non-Competitive Antagonism

Answer 14

Some antagonists can form covalent bonds with the active site on the receptor and this irreversibly blocks it. This is a non-competitive process because the irreversible antagonist cannot be displaced by the agonist which leads to a reduction in the maximal effect and this reduction in agonist efficacy.

Question 15

Allosteric Antagonist

Answer 15

They bind to the site different from the agonist binding site and induce conformational change which prevents the agonist from activating the receptor.

Question 16

Therapeutic Index

Answer 16

Not everyone will experience the same effect from the same dose of drug. The therapeutic index helps measure the relative safety of a drug.

Question 17

Zero-Order Kinetics

Answer 17

The amount of drug eliminated is independent of drug concentration in the body.

Question 18

First-Order Kinetics

Answer 18

Most drugs are eliminated by first order kinetics. The rate of elimination is directly proportional to the concentration of the drug in the body.

Question 19

Steady State

Answer 19

Rate of drug administration = rate of drug elimination (equilibrium).

Question 20

Absorption

Answer 20

the process by which a drug enters the body from its site of administration and enters the general circulation (note the lumen of the G.I. tract is outside the body).

Question 21

Distribution

Answer 21

the transport of drug by the general circulation. Drugs most often leave the blood and enter perfused tissues. Once within a tissue further, reversible, distribution dictated by a concentration gradient, may occur by diffusion (or carrier-mediated transport).

Question 22

Metabolism

Answer 22

the process by which tissue enzymes (principally in the liver – hepatic metabolism) catalyse the chemical conversion of a frequently lipid soluble drug to an often less active and more polar form that is more readily excreted from the body.

Question 23

Excretion

Answer 23

the processes that remove the drug, or its metabolites, from the body (principally the kidneys – renal excretion), but other routes may be important for specific agents.

Question 24

The Micturition Reflex

Answer 24

an example of the coordinated activity of the sympathetic and parasympathetic divisions of the ANS in terms of bladder control.