Lecture 02 - Pharmacokinetics and Pharmacodynamics

Question 1

What are the mechanisms of drug clearance

Answer 1

kidney, bile, milk, saliva, lungs, feces, sweat

Question 2

How many half lives does it take to reach steady state

Answer 2

five

Question 3

What is the drug elimination half life

Answer 3

the time required for the amount of drug in the body or its concentration to fall by 50%

Question 4

How many half lives does it take to rid the body of the drug

Answer 4

five

Question 5

What is a maintenance dose

Answer 5

amount of drug administered to maintain a desired steady state drug concentration in the body

Question 6

What makes a drug a TDM candidate

Answer 6

narrow therapeutic range, clinically dangerous or difficult to interpret for over or underdosing, high biological variation, concentration proportional to clinical effect, availability of a standardized reliable assay, concentration changes with polypharmacy, inhibition, induction, diet ect.

Question 7

What is first order elimination

Answer 7

rate of clearance of the drug is proportional to the drug concentration

Question 8

What is zero order elimination

Answer 8

rate of clearance of the drug is constant regardless of drug concentration

Question 9

What kind of drugs follow zero order kinetics

Answer 9

drugs that saturate elimination mechanisms such as alcohol, phenytoin, aspirin

Question 10

How are drugs eliminated from the body

Answer 10

liver and kidneys

Question 11

What is enterohepatic recirculation

Answer 11

a drug that keeps cycling from the intestines to the liver (constantly converted from active to inactive)

Question 12

What are the steps of hepatic elimination of drugs

Answer 12

cell dissociation, protein dissociation, hepatocyte uptake, metabolism, biliary excretion, bacteria hydrolysis, enterohepatic re-circulation

Question 13

What are the processes of renal elimination

Answer 13

passive glomerular filtration, active proximal tubular secretion, passive distal tubular reabsorption

Question 14

What are factors that effect renal excretion

Answer 14

drug properties, plasma protein binding, fluid intake, urine pH, other drugs, kidney function

Question 15

How is bioavailability effected for neonates and infants

Answer 15

decreased gastric acidity, prolonged gastric residence time, slower intestinal motility, transporter function varies with maturation, increased intestinal permeability, increased skin permeability, decreased bile salts

Question 16

How is bioavailability effected for geriatrics

Answer 16

delayed gastric emptying, decreased absorption surface, decreased GI motility

Question 17

How is distribution effected for neonates and infants

Answer 17

increased total body water to body fat ratio causes increased Vd for hydrophilic drugs, decreased binding capacity of albumin, decreased concentrations of albumin and alpha one acid glycoprotein, high bilirubin displaces drugs

Question 18

How is distribution effected for geriatrics

Answer 18

decreased total body water to body fat ratio decreases Vd for hydrophilic drugs, decreased plasma protein binding

Question 19

How is clearance effected for neonates and infants

Answer 19

immature renal function, unique metabolic pathways, immature liver function

Question 20

How is clearance effected for geriatrics

Answer 20

slight decline in renal function, slight decline in hepatic function, phase I metabolism, no change in phase II metabolism