[7] Pharmacokinetics in Special Conditions

Question 1

Are most active drugs Basic or Acidic?

Answer 1

Basic

Question 2

Assessment of Renal Function (3)

Answer 2

1. Hourly urine output
2. Amount of circulating Urea and Nitrogen Concentration
3. Creatine clearance and GFR

Question 3

Average Hourly Urine Output?

Answer 3

60mL

Question 4

Limitation of Creatinine Clearance

Answer 4

Less muscle bulk or in elderly patients would give a lower than average creatinine clearance value

Question 5

Formula: Dose Adjustment Factor

Answer 5

1 / F (kf -1) +1

F: Fraction of Drug Excreted Unchanged
Kf: Relative Kidney function calculated by dividing actual creatinine clearance with 120 mL/min

Question 6

Example:

Digoxin F = 0.75
If the oral digoxin dose is 0.25mg orally, what is the DAF for a patient with creatinine clearance of 60 mL/minute?

Answer 6

DAF = 1/0.75 (60/120 - 1) + 1
= 1.6

Adjusted dose is 0.25 / 1.6 or 1.6mg daily

Question 7

Conditions for Validity of DAF

Answer 7

o Only for first order kinetic (one compartment) in the therapeutic concentration range →What you excrete is proportionate to what’s in your body
o Metabolites of the drug are not active and non-toxic; otherwise, it would follow a 2 compartment model
o No difference in the absorption, metabolism and distribution of the drug between normal and uremic patients
o No alterations in drug sensitivity in uremic patients
o A direct relationship is assumed between ClCr and the renal elimination of the drug
o Stable kidney function

Question 8

Reduction in Drug Dosage Depends on? (3)

Answer 8

1. Therapeutic Index of Drug
2. Proportion of Renal Clearance of Total Clearance
3. Severity of Renal Impairment

Question 9

How does renal damage affect drugs in terms of protein bound forms?

Answer 9

With less albumin present, the drugs that are unbound are in their active form and as such would be stronger than usual

Question 10

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Amoxicillin

Answer 10

Slight decrease

Question 11

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Bilirubin

Answer 11

Decrease

Question 12

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Cefazolin

Answer 12

Decrease

Question 13

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Furosemide

Answer 13

Decrease

Question 14

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Indomethacin

Answer 14

Normal

Question 15

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Cefoxitin

Answer 15

Decrease

Question 16

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Clofibrate

Answer 16

Decrease

Question 17

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Diazoxide

Answer 17

Decrease

Question 18

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Phenobarbital

Answer 18

Decrease

Question 19

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Phenytoin

Answer 19

Decrease

Question 20

[Binding to Plasma Proteins in Patients with Poor Renal Function]

Salicyclate

Answer 20

Decrease

Question 21

How do you achieve diuresis in patients with renal disease?

Answer 21

Loop Diuretics

Question 22

What can you never give pregnant women at any stage?

Answer 22

ACE Inhibitors, they would cause renal damage

Question 23

Most important drug you cannot give to patients with renal failure

Answer 23

Potassium, since only kidneys excrete K

Highly cardiotoxic

Question 24

Most Common of Pathway of Biotransformation in the Liver?

A. Conjugation
B. Oxidation
C. Sulfuridation
D. Glucorination

Answer 24

A

Question 25

Filipinos are rapid acetylators

Answer 25

Hi! This is a note card! Give yourself a 5. Unless you just read this now, maybe give yourself a 3. Then a 5!

Question 26

2 Examples of Hetapic Derangement that can Affect Drug Fate and Action

Answer 26

1. Hepatocellular loss with absolute decrease in quantity of Drug Metabolizing Enzymes 2. Effect of Altered Perfusion

Question 27

Which drug will give more adverse reactions with cirrhosis? Lidocaine ER: 0.9 Antipyrine ER: 0.1

Answer 27

Lidocaine, because of the high extraction ratio

Question 28

Large volume of distribution indicates high affinity of drug to tissues or plasma?

Answer 28

Tissues

Question 29

Define: Extraction Ratio

Answer 29

Extent to which a drug is cleared in one passage in the liver

Question 30

What are the drugs that can have prolonged or unchanged Half-Life?

Answer 30

Pentobarbital Phenytoin Prednisone Tolbutamide TP3

Question 31

Liver problems cause losses of which vitamin?

Answer 31

Vitamin K

Question 32

Examples of Drugs Extensively Metabolized by the Liver

Answer 32

Benzodiazepines NSAIDs Opiods

Question 33

Plasma Volume increases by how much during pregnancy?

Answer 33

40-50%

Question 34

Effect on: Plasma Albumin Levels Plasma Total Protein A1 Acid Glycoprotein

Answer 34

PA: Decreases PTP: The Same A1AG: The Same

Question 35

Example of a drug that would increase in concentration during pregnancy?

Answer 35

Probenicin Drug with high protein binding affinity

Question 36

What causes the delay in gastric emptying time in pregnant women?

Answer 36

Progesterone, increased during pregnancy

Question 37

[Pregnancy] What happens to acid secretion during the 1st, 2nd, and 3rd trimester?

Answer 37

1st: Decreased 2nd: Decreased 3rd: Increased

Question 38

Effect of Smoking on Babies in Utero

Answer 38

Low Birth Weight

Question 39

Effect of Drugs on Fetus Before 20th Day

Answer 39

All-or-Nothing Effect

Question 40

Effect of Drugs on Fetus 3rd to 8th Week (3)

Answer 40

1. No Measurable Effect/Abortion 2. Permanent Subtle Metabolic/Functional Defect 3. Sublethal Gross Anatomic Defect

Question 41

Effect of Drugs on Fetus 2nd and 3rd Trimester

Answer 41

Altered growth and function of normally formed organ and tissues

Question 42

Most delicate organ that can be affected at any point of growth in utero and onward

Answer 42

Reproductive System | The Brain is also counted