[7] Pharmacokinetics in Special Conditions Flashcards

1
Q

Are most active drugs Basic or Acidic?

A

Basic

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2
Q

Assessment of Renal Function (3)

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

Average Hourly Urine Output?

A

60mL

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4
Q

Limitation of Creatinine Clearance

A

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

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5
Q

Formula: Dose Adjustment Factor

A

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

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6
Q

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?

A

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

Adjusted dose is 0.25 / 1.6 or 1.6mg daily

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7
Q

Conditions for Validity of DAF

A

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

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8
Q

Reduction in Drug Dosage Depends on? (3)

A
  1. Therapeutic Index of Drug
  2. Proportion of Renal Clearance of Total Clearance
  3. Severity of Renal Impairment
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9
Q

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

A

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

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10
Q

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

Amoxicillin

A

Slight decrease

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11
Q

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

Bilirubin

A

Decrease

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12
Q

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

Cefazolin

A

Decrease

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13
Q

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

Furosemide

A

Decrease

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14
Q

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

Indomethacin

A

Normal

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15
Q

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

Cefoxitin

A

Decrease

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16
Q

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

Clofibrate

A

Decrease

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17
Q

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

Diazoxide

18
Q

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

Phenobarbital

19
Q

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

Phenytoin

20
Q

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

Salicyclate

21
Q

How do you achieve diuresis in patients with renal disease?

A

Loop Diuretics

22
Q

What can you never give pregnant women at any stage?

A

ACE Inhibitors, they would cause renal damage

23
Q

Most important drug you cannot give to patients with renal failure

A

Potassium, since only kidneys excrete K

Highly cardiotoxic

24
Q

Most Common of Pathway of Biotransformation in the Liver?

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

25
Filipinos are rapid acetylators
Hi! This is a note card! Give yourself a 5. Unless you just read this now, maybe give yourself a 3. Then a 5!
26
2 Examples of Hetapic Derangement that can Affect Drug Fate and Action
1. Hepatocellular loss with absolute decrease in quantity of Drug Metabolizing Enzymes 2. Effect of Altered Perfusion
27
Which drug will give more adverse reactions with cirrhosis? Lidocaine ER: 0.9 Antipyrine ER: 0.1
Lidocaine, because of the high extraction ratio
28
Large volume of distribution indicates high affinity of drug to tissues or plasma?
Tissues
29
Define: Extraction Ratio
Extent to which a drug is cleared in one passage in the liver
30
What are the drugs that can have prolonged or unchanged Half-Life?
Pentobarbital Phenytoin Prednisone Tolbutamide TP3
31
Liver problems cause losses of which vitamin?
Vitamin K
32
Examples of Drugs Extensively Metabolized by the Liver
Benzodiazepines NSAIDs Opiods
33
Plasma Volume increases by how much during pregnancy?
40-50%
34
Effect on: Plasma Albumin Levels Plasma Total Protein A1 Acid Glycoprotein
PA: Decreases PTP: The Same A1AG: The Same
35
Example of a drug that would increase in concentration during pregnancy?
Probenicin Drug with high protein binding affinity
36
What causes the delay in gastric emptying time in pregnant women?
Progesterone, increased during pregnancy
37
[Pregnancy] What happens to acid secretion during the 1st, 2nd, and 3rd trimester?
1st: Decreased 2nd: Decreased 3rd: Increased
38
Effect of Smoking on Babies in Utero
Low Birth Weight
39
Effect of Drugs on Fetus Before 20th Day
All-or-Nothing Effect
40
Effect of Drugs on Fetus 3rd to 8th Week (3)
1. No Measurable Effect/Abortion 2. Permanent Subtle Metabolic/Functional Defect 3. Sublethal Gross Anatomic Defect
41
Effect of Drugs on Fetus 2nd and 3rd Trimester
Altered growth and function of normally formed organ and tissues
42
Most delicate organ that can be affected at any point of growth in utero and onward
Reproductive System | The Brain is also counted