Pharmacology Unit 2

Question 1

What is Biotransformation (Drug Metabolism)? What is the result of this?

Answer 1

Chemical changes that take place in the drug following administration.
- Results in an altered version of the original compound known as “a metabolite”, different ways they are altered are:
–Oxidation:O2 is added or H is removed from compound. (Predominant method)
–Reduction: Remove O2 or add H
–Hydrolysis: The drug is broken into separate parts
–Conjugation

Question 2

What are the organs responsible for biotransformation?

Answer 2

• Liver
• Lungs
• Kidney
• GI
• Integument

Question 3

With Biotransformation, what is Enzyme Induction?

Answer 3

• Prolonged use of certain drugs “induces” the body to adjust and enzymatically destroy the drug more rapidly that expected
• Usually more metabolizing enzymes are being manufactured or fewer are being degraded
• This is one of the reasons “Tolerance” occurs
• Alcohol, cigarette, herbal products or environmental toxins also cause enzyme induction

Question 4

What is the primary site of Drug Excretion?

Answer 4

Kidneys

*Also respiratory (drugs can change into gaseous form, Bowel (Biliary excretion)

Question 5

With Drug Elimination Rates, what is Clearance?

Answer 5

• The rate at which drugs are removed from the body
• Helps to determine how long a drug will remain in the bloodstream

Question 6

With Drug Elimination Rates, what is Biological Half-Life (t1/2)?

Answer 6

• The amount of time for a drug to decrease concentration in the plasma by 1/2
• Shorter t1/2 may require more frequent doses
• Hepatic disease may increase t1/2

Question 7

If a drug has a half life of 10 seconds, and you give a patient a dose of 6mg. After 30 seconds how much of the drugs remains?

Answer 7

• In 10 seconds : 3mg
• In 20 seconds : 1.5mg
• In 30 seconds : 0.75mg

Question 8

What is Adenylate Cyclase?

Answer 8

An enzyme located on the thinner surface of many cell membranes; it is important in mediating biochemical changes in the cell in response to drug and hormone stimulation

Question 9

Drug receptors typically affect cell function in what 3 ways?

Answer 9

• By acting as an ion channel and directly altering membrane permeability
• By acting enzymatically to direct influence function within the cell
• By being linked to regulatory proteins that control other chemical and enzymatic processes with-in the cell

Question 10

What are Intracellular Receptors? What are they specific for?

Answer 10

These receptors are within the cell cytoplasm or nucleus
- Intracellular receptors specific for:
–Endogenous Hormones
–Hormone like drugs

Question 11

What do Hormone Receptors affect?

Answer 11

Hormone receptor complexes affect gene expression and messenger RNA transcription
–Steroids
–Thyroid

Question 12

With Drug Receptor Interactions, What is the definition of Affinity?

Answer 12

The mutual attraction between a drug and a specific cellular receptor

Question 13

With Drug Receptor Interaction, what is Allosteric Modulators?

Answer 13

Substances that bind to a cell receptor and alter the receptor’s affinity for specific drugs; Common allosteric modulators include guanine nucleotides, ammonium ions, calcium, and other divalent cations

Question 14

What is Drug Selectivity?

Answer 14

A drug is selective if it affects only one type of cell or tissue and produces a specific physiological response

Question 15

With the Classification of Drugs, what is the difference between Agonist and Antagonist?

Answer 15

Agonist: A drug that binds to a receptors and causes some change in cell function
- Has both affinity and efficacy (Drug will bind and cause an effect)

Antagonist: A drug that binds to a receptor but does not change in cell activity `

Question 16

What is the difference between Competitive and Non-Competitive Antagonist?

Answer 16

Competitive Antagonist: Vie for the same receptor as the agonist; the agonist and the competitive antagonist have equal opportunity to occupy the receptor.

Noncompetitive Antagonist (aka - irreversible antagonist): Form strong, essentially permanent, bonds to the receptor

Question 17

What is Cyclic Adenosine Monophosphate (cAMP)?

Answer 17

The ring shaped conformation of adenosine monophosphate, which is important in acting as a second messenger in mediating the intracellular response to drug stimulation

Question 18

What is Desensitization?

Answer 18

A brief transient decrease in the responsiveness of cellular receptors to drug effects

Question 19

What is Down-Regulation?

Answer 19

A prolonged decrease in the number and/or sensitivity of drug receptors, usually occur-ring as a compensatory response to overstimulate of the receptors

Question 20

What is Gamma-aminobutyric Acid (GABA)?

Answer 20

An inhibitory neurotransmitter in the brain and Spinal Cord

Question 21

What are G proteins?

Answer 21

Proteins that bind with guanine nucleotides and regulate cell activity. G proteins often serve as a link between surface receptors and ion channels or intracellular enzymes such as adenylate cyclase

Question 22

What are Second Messenger?

Answer 22

The term applied to com-pounds formed within the cell, such as cyclic AMP. The second messenger initiates a series of biomechanical changes within the cell following stimulation of a receptor on the cell’s outer surface by drugs, hormones and so on

Question 23

What is Selective Estrogen Receptor Modulator (SERM)?

Answer 23

A drug that activates estrogen receptors on bone and vascular tissues, while blocking estrogen receptors on breast and uterine tissues. These drugs can be used to enhance bone mineralization and to prevent certain cancers