General principles of Pharmacology

Question 1

General principles of pharmacology are:

Answer 1

(1) The factors that affect the actions of drugs.
(2) Factors that affect drug reactions.
(3) Various types of drug interactions.
(4) Factors influencing drug response interactions.

Question 2

Pharmacokinetic: Activities of the drug after it enters the body. Pharmacokinetics is the study of drug absorption, distribution, metabolism, and excretion.

Answer 2

A fundamental concept in pharmacokinetics is drug clearance, that is, elimination of drugs from the body.

Question 3

Absorption: The transfer of the drug from the body fluids to the tissues.

Answer 3

(1) Active absorption: Carrier molecule such as a protein or enzyme actively moves the drug across the membrane.

Question 4

2) Passive absorption: Diffuse across a membrane from area of higher concentration to an area of lower concentration (Water Soluble Drugs).

Answer 4

(3) Pinocytosis: Cells engulf the drug particle across the cell membrane.

Think packman!

Question 5

(4) Bioavailability is a subcategory of absorption. It is the percentage of the administered drug dose that reaches the systemic circulation.

Answer 5

For drugs taken orally bioavailability occurs only after the medication has been absorbed and metabolized by the liver.
Oral drugs that have a first pass hepatic metabolism may only have a bioavailability of 20-40% as opposed to I.V medications that have a 100% bioavailability.

Question 6

Factors that alter Bioavailability are:

Answer 6

(1) The drug from (e,g tablet, capsule, sustained release, liquid, trans-dermal patch, inhalation).
(2) Route of administration.
(3) Changes in Liver metabolism caused by dysfunction.
(4) GI mucosa and motility.
(5) Food and drugs.
(6) Solubility: Drugs that are fat soluble are absorbed faster than water-soluble drugs.

Question 7

Distribution: Movement of drug throughout the body typically on proteins (albumin).

Answer 7

(1) Therapeutic effect: Drug levels in blood to produce desired effect. (a) Too high = toxic
(b) Too low = decreased effect

Question 8

Metabolism: Chemical reaction by with liver converts drug to inactive compound.

Answer 8

(1) Metabolism occurs in the Liver, Kidneys, lungs, plasma, and intestinal mucosa.
(2) A patient with liver disease may require a lower dose of a medication that is metabolized by the liver or a different medication that is not metabolized by the liver.

Question 9

Excretion: Elimination of drugs from the body.

Answer 9

(1) Kidney excretes the inactive compounds from the body in the urine.

Question 10

Half - Life: Time required for the body to eliminate 50% of the drug.

Answer 10

(1) Kidney, Liver disease and old age can increase the half-life increasing risk of toxicity.

Question 11

Pharmacodynamics: Drug’s actions and effects within the body.

Answer 11

(1) Primary or desired effect.

(2) Secondary effects (side effects) – desired or undesired.

Question 12

Physical dependence:

Answer 12

A compulsive need to use a substance repeatedly to avoid mild to severe withdrawal symptoms.

Question 13

Psychological dependence:

Answer 13

A compulsion to use a substance to obtain a pleasurable experience.

Question 14

Pharmacogenetic disorder:

Answer 14

A genetically determined abnormal response to normal doses of a drug.

Question 15

Receptor:

Answer 15

A specialized macromolecule that binds to the drug molecule, altering the function of the cell and producing the therapeutic response.

Question 16

Alterations in Cellular Environment:

Answer 16

A drug that alters cellular function can increase or decrease the physiologic functions of the cell Ex: Increased heart rate, decrease blood pressure.

Question 17

Therapeutic Response:

Answer 17

Alteration of cell to achieve the desired response.

Question 18

Agonist:

Answer 18

Drug that binds with a receptor to produce the therapeutic response.

Question 19

Antagonist:

Answer 19

Drug binds to receptor stronger than the agonist thus producing no pharmacologic effect Ex: Narcan is antagonist to morphine.

Question 20

Adverse reaction:

Answer 20

Undesirable drug effects.

Question 21

Allergic reaction:

Answer 21

A drug reaction that occurs because the individual’s immune system views the drug as a foreign substance.

Question 22

Drug idiosyncrasy:

Answer 22

Any unusual or abnormal reaction to a drug that a patient can have, that do not occur in the vast majority of patients taking the same drug.

Question 23

Drug tolerance:

Answer 23

A decreased response to a drug, requiring an increase in dosage to achieve the desired effect.

Question 24

Cumulative drug effect:

Answer 24

A drug effect that occurs when the body has not fully metabolized a dose of a drug before the next dose is given.

Question 25

Toxic: A harmful drug effect if it is delivered in high dose or when blood concentration levels exceed therapeutic level (as seen in patients with Liver or Kidney disease).

Answer 25

(1) May be reversible or irreversible depending on organ/tissue damage. Liver has ability to regenerate but hearing loss may be irreversible due to streptomycin toxic reaction.
(2) You have to know the signs and symptoms of toxicity for drugs you are giving.

Question 26

Pharmacogenetics Reactions:

Answer 26

Inherited traits that cause abnormal metabolism of the drug

Question 27

Pharmaceutic phase:

Answer 27

The dissolution of a drug. Usually applying to the breakdown of tablets.

Question 28

Drug Interactions:

Answer 28

When one drug interacts with or interferes with the action of another drug.

Question 29

Additive drug reaction:

Answer 29

A reaction that occurs when the combined effect of two drugs is equal to the sum of each drug given alone.

Question 30

Synergism:

Answer 30

A drug interaction that occurs when drugs produce an effect that is greater than the sum of their separate actions.

Question 31

Antagonist Drug Reaction:

Answer 31

When one drug interferes with the action of another, causing neutralization or a decrease in the effect of one drug.

Question 32

Drug - Food Interactions:

Answer 32

Drug given orally, food may impair or enhance its absorption.

Question 33

Age:

Answer 33

immature or aging organ function affects metabolism of a drug.

Question 34

Weight:

Answer 34

Average weight is approximately 150 lb for both men and women. A medication may need to be increased or decreased.

Question 35

Gender:

Answer 35

Women require smaller dose due to differences in body fat and water ratio compared to men.

Question 36

Disease:

Answer 36

Liver disease may affect ability to metabolize or detoxify a drug.

Question 37

Route of Administration:

Answer 37

IV drug produce the most rapid response than any other method.

Question 38

Drug Use and Pregnancy:

Answer 38

(1) Teratogen: A substance that may produce physical or functional defects in a human embryo or fetus.
(2) Federal Drug Administration established five categories:
(a) Pregnancy CAT: A, B, C, D, X