Bioavailability, ADME, and Therapeutic Equivalence

Question 1

ADME

Answer 1

absorption
distribution
metabolism
excretion

Question 2

absorption

Answer 2

concerns the factors involved in that process

Question 3

why might a drug be poorly absorbed in the body

Answer 3

because its poorly soluble, chemically unstable (pH imbalance in the stomach) , or because of the intestinal tract

Question 4

why must drug distribution system exist?

Answer 4

for the drug to travel to its target site

Question 5

what plays a vital role in distribution?

Answer 5

the bloodstream - as it collects drug from one part of the body and sends it to others

Question 6

what factors influence drug distribution

Answer 6

• whether the drug can cross blood-brain barrier
• blood flow rates are different in different parts of the body
• molecular size of the drug compound
• polarity of the drugs

Question 7

what is an example of a high polar drug

Answer 7

aminoglycosides - they do not cross lipid membranes so cannot be given orally

Question 8

as the drug enters the body and while it is being distributed, it undergoes various stages of ____________ ?

Answer 8

metabolism

Question 9

when does metabolism occur?

Answer 9

when the drug begins to undergo some form of chemical transformation

Question 10

what are prodrugs?

Answer 10

meds administered to the body in their inactive form
once metabolized, they are transformed into active ingredients to exert their therapeutic effect on the target site

Question 11

Cytochrome P450

Answer 11

vast collection of enzymes that coordinate hepatic metabolic reactions

Question 12

acetaminophen is metabolized by the liver by what?

Answer 12

CYP 450 enzymes

Question 13

how are compounds and metabolites eliminated?

Answer 13

via the kidneys - in the form of urine and biliary and fecal excretion

Question 14

what is the forgotten means of excretion?

Answer 14

exhalation

Question 15

what is exhalation?

Answer 15

removing drug compounds via breathing
this is how anesthetic gases are eliminated

Question 16

ADME -T

Answer 16

T refers to toxicity

Question 17

Bioavailability

Answer 17

percentage of drug that reaches the systemic circulation (or cardiovascular system) to allow the drug to travel through blood vessels and other barriers to reach its target site of action

Question 18

amoxicillin has a bioavailability of ____ percent?

Answer 18

95%
this means that 95% of the drug reaches the systemic circulation and the 5% does not

Question 19

Prozac (fluoxetine) is an ____ medication

Answer 19

anti-depressant

Question 20

what is the bioavailability of fluoxetine?

Answer 20

70%
meaning 30% was metabolized and removed by the body before it reached its target site

Question 21

bioavailability of alendronic acid?

Answer 21

0.7%

Question 22

drugs administered via the IV route has ____ bioavailability

Answer 22

almost or near 100%

Question 23

what factors impact bioavailability?

Answer 23

• physical properties of the drug
• diseases
• age
• gender
• food
• drug formulation

Question 24

Bioequivalence

Answer 24

term used to review the clinical and biological effects of two proprietary medicines

Question 25

when are two drugs bioequivalent?

Answer 25

if they demonstrate, for all intents and purposes, the same clinical and biological effects

Question 26

what is the FDA’s definition of bioequivalence?

Answer 26

“the absence of a significant difference in the rate and extent to which the active ingredient or active moiety in pharmaceutical equivalents or pharmaceutical alternatives becomes available at the site of drug action when administered at the same molar dose under similar conditions in an appropriately designed study.