Pharmacodynamics, kinetics, genetics, drug reactions, dosing regime

Question 1

Define medication half life

Answer 1

the time it takes for the amount of a drug’s active substance in your body to reduce by half

Question 2

Define pharmacodynamics

Answer 2

What the drug does to the body

Question 3

Define pharmacokinetics

Answer 3

What the body does to the drug

Question 4

What are the molecular targets for drugs?

Answer 4

Carriers, Ions, enzymes, receptors

Question 5

How the body affects a specific drug after administration

Answer 5

A - administration
D - distribution
M - metabolism
E - excretion

Question 6

Define therapeutic range of a drug

Answer 6

To keep drug concentration in therapeutic range another dose must be administered on or near the half life

Question 7

What does the therapeutic range do

Answer 7

Helps to ensure high probability of drug producing desired effects and low probability of drug producing adverse effects.

Question 8

Define steady state

Answer 8

refers to a condition in which the rate of administration or intake of a drug is equal to the rate of elimination or clearance of that drug from the body. When a drug is in a steady state, the concentration of the drug in the bloodstream remains relatively constant over time.

Question 9

Drug metabolism - zero order kinetics

Answer 9

Constant amount per unit time is metabolised
Rate does not increase as drug concentration increases
E.g. alcohol, phenytoin and occurs in overdose situations

Question 10

Drug metabolism - first order kinetics

Answer 10

The amount of drug eliminated from the body is proportional to the drug plasma concentration
Rate increases as drug concentration increases
Most drugs follow first order kinetics

Question 11

What are the age related changes on the body system?

Answer 11

Metabolism (liver mass shrinks, hepatic blood flow decreases), Drug receptor interaction (brain receptors become more sensitive), circulation vascular nerve control is less stable), excretion (GFR is reduced, nephron declines, blood flow and waste removal slows, age related changes lengthen half life), distribution (Lean body mass falls, adipose stores increase, body water declines), absorption (Gastric motility rate slows, absorption capacity of cells decline)

Question 12

What happens with age related changes on the body relating to metabolism

Answer 12

decreased blood flow and decreased enzyme activity can result in decreased hepatic clearance and potential increase in plasma = toxicity

Question 13

What happens with age related changes on the body relating to excretion

Answer 13

Decreased blood flow to kidneys, decreased GFR, decreased nephrons results in decrease excretion of drugs = increase in plasma concentration levels and prolonged half life

Question 14

What happens with age related changes on the body relating to absorption

Answer 14

Decrease gastric acid secretion can alter the decomposition and absorption of drugs.
Decrease GI motility can slow the absorption of medications in the GI tract

Question 15

What happens with age related changes on the body relating to distribution

Answer 15

Decreased total body water, plasma, volume and ECF = increase risk of toxicity of water soluble drugs (may need to reduce dose)
Increase in body fat = increase volume of distribution of lipid soluble drugs

Question 16

Define loading dose

Answer 16

A larger than normal dose administered as the first in a series of doses. It is administered to achieve a therapeutic amount in the body more rapidly than would occur only by accumulation of the repeated smaller doses.

Question 17

Define potency

Answer 17

the amount of drug required to produce 50% of the drugs maximal effect, the more potent the drug, the lower the dose required for a given effect

Question 18

Define ligand

Answer 18

a substance that forms a complex with a receptor to serve a biological purpose.

Question 19

Define creatinine clearance

Answer 19

the volume of blood plasma cleared of creatinine per unit time. It is a rapid and cost-effective method for the measurement of renal function.

Question 20

Define pro drug

Answer 20

a drug that is converted to its active form after absorption

Question 21

What is an adverse drug reaction Type A?

Answer 21

Predictable, unintended, and undesirable response to a drug.

Question 22

What is an adverse drug reaction Type B?

Answer 22

Unpredictable, unintended, and undesirable response to a drug.