PK Physiology Quiz 13

Absorption: Physiological Variable: decrease gastric and intestinal motility Age Group: neonates, infants PK Results:

? questionable

Absorptions physiological Variable: increase gastric and intestinal motility Age group: older infants, children PK Result:

? questionable changes with time

Hepatic blood flow is _______% of cardiac output.

27%

Characteristics/ Considerations of Elderly

Health Increased risk/incidence of physiologic deficiency and pathophysiology Institutionalization Increased share of hospital and long-term-care beds Drug use Consume more prescription and nonprescription drugs Drug effects Increased incidence of ADEs

Which population is likely to have the highest body percentage of adipose? a. Elderly female b. Young adult male c. Young adult female

a

A drug is entirely dependent on hepatic blood flow for its elimination. If the patient is receiving a continuous infusion of the drug, what will theoretically happen to the steady-state concentration if cardiac output decreases 25%? a. The concentration will increase 25% b. The concentration will decrease 25% c. The clearance will decrease 25% d. The CL will increase 25%

a.

Elderly Effect: Protein Binding Altered Physiology: a. serum albumin b. AAG c. Gammaglobulin d.RBC binding clinical considerations:

a. decrease b. increased <-> c. increased <-> d. increased <-> increased fraction of highly bound acidic drugs decrease/no change free fraction of highly bound basic drug

Elderly effect: absorption altered physiology a. gastric acid secretion b. gastric pH c. GI Blood Flow d. pancreatic trypsin e. number of absorbing cells f. GI motility clinical consideration:

a. decrease b.increase c.decrease d.decrease e. decrease f.decrease clinical consideration: altered dissolution rate, possible decreased absorption rate-"longer time" for onset of effect

Elderly Effect: Metabolism (hepatic) altered physiology: a. enzyme inductibility b. hepatic blood flow c. hepatic mass d. acetylation e. alcohol dehydrogenase f. glucuronidations g. MFO (P450s) clinical considerations

a. decrease/no change b. decrease c. decrease d. no change e. no change f decrease/no change g. decrease/no change apparent decrease in metabolism and clearance of some drugs (also influenced by environmental factors)

Elderly Effect of Elimination Altered Physiology a. GFR b. Renal plasma flow c. active secretion clinical considerations

a. decreased b. decreased c. decreased decreased renal clearance

Absorption: physiological variable: increased gastric pH age group: neonates, infants, young children pK results a. basic drug b. Acidic drug

a. increase F b. decrease f

Elderly Effect: distribution body composition Altered Physiology: a. total body water b. lean body weight c. body fat clinical considerations:

a.decrease b.decrease c.increase (females >males) polar drugs tend to have a decreased volume of distribution

Factors: physiologic variables

age;definitions, age:comparisons, age:changes, health status, drug therapy, nutritional status, environmental

A drug, which obeys linear pharmacokinetics, distributes throughout total body water (~42L). Consider the following figure: What will the volume of body fluid be if the patient has their right leg amputated at the hip? a. 42 L b. 35.3 L c. 21 L d. 17 L

b

An elderly patient with decreased hepatic function may be expected to have which of the following related to a hepatically metabolized drug at the standard dose. a. Increase CL b. Longer t½ c. Lower concentrations d. Shorter time to steady-state

b

D.S. is in the emergency department, having suffered a myocardial infarction. Thirty-six hours later, a MUGA scan is performed and reveals that D.S. has a cardiac output that 67% the "normal" value. Considering that D.S. is on lidocaine to prevent arrhythmias, and lidocaine's clearance is directly related to hepatic blood flow, what is the percentage decrease in the clearance of lidocaine? a. 67% b. 33% c. 50% d. 27% c. 78%

b

Drug B is lipophilic. In which of the following patients is the volume of distribution likely to be greatest? a. T.J. a 25 year old male athlete. b. S.J. a 68 year old female. c. H.I. a 68 year old male. d. R.T. a 33 year old female.

b

Drug X is very lipophilic. Which statements is/are correct? a. It is likely the volume of distribution would be lower in elderly patients as compared to young adults. b. It is likely the volume of distribution would be higher in elderly patients as compared to young adults. c. Because of decreased total body water, the volume of distribution of drug X would be decreased in the elderly patient versus the young adult. d. Drug X would have the same volume of distribution, because drug X is only half protein bound. e. None of the above

b

True or False. Decreased cardiac output does not effect blood flow to the gastrointestinal tract. a. True b. False

b

Which of the following, when administered with drug A (a tablet dosage form for epilepsy) is likely to result in increased gastric emptying? a. 1 oz. of water b. 8 oz. of water c. 4 oz. of water d. Swallowing the tablet without water

b

Cardiac output is approximately 5.6 liters per minute. Liver blood flow is what percent of cardiac output? a. 3.7% b. 2.6% c. 27% d. 2.2% e. 4.3%

c

Consider the otherwise healthy individuals listed below: Ms. A Ht. 5'2" Wt. 110 lbs Age 18 years Ms. B Ht. 5'2" Wt. 110 lbs Age 25 years Ms. C Ht. 5'2" Wt. 110 lbs Age 72 years Ms. D Ht. 5'2" Wt. 110 lbs Age 55 years Each of the above individuals has a serum creatinine value of 1.1 mg/dL (normal range 0.8 mg/dL to 1.4 mg/dL) Which individual likely has the worst renal function? a. Ms. A b. Ms. B c. Ms. C d. Ms. D

c

If the drug concentration, following an 84 mg dose, is 2 mg/L in total body water in an otherwise healthy patient, what will the concentration be, following a similar dose, in a patient who has had their right leg amputated at the hip? a. 2 mg/L b. 0.8 mg/L c. 2.4 mg/L d. 1 mg/L

c

In which of the following patients is a serum creatinine value least believable as a marker of glomerular filtration rate? a. F.L. a malnourished underweight 29 year old male with AIDS. b. E.D. a healthy 24 year old college student. c. A.S. a 43 year old female with liver failure. d. a and c only e. All of the above

d

Mrs. Jones, a 78 year old patient was discovered to have a cardiac output that was 30% lower than previously noted. Based on this information which of the following statements is/are correct? a. Because cardiac output is decreased, it is likely that drug elimination would be decreased. b. Decreased cardiac output likely decreases blood flow to the gastrointestinal tract and may alter the absorption of some orally administered drugs. c. The decreased cardiac output would result in increased drug absorption from an intramuscular injection. d. a and b only. e. All of the above.

d

Absorption: physiological variable: decreased bile acids age group: neonates Pk Result:

decrease F

True or False. Typically, because of altered physiology, an elderly patient will require a higher dose of a renally (kidney) eliminated drug

false

Metabolism Physiological Variable: ↑ Enzyme capacity Age Group: Young Children PK Result:

↑ CL ↓ t½

Distribution: Physiological Variable: ↑ Total body water ↑ Extracellular water Age Group: Neonates, infants PK Result:

↑ Vd

Distribution physiological Variable: ↓ [Albumin] Age Group: Neonates, infants PK Result:

↑ Vd ? [Unbound drug]

Excretion Physiologic Variable: ↓ GFR Age Group: Neonates, infants PK Result:

↓ CL ↑ t½

Metabolism physiological Variable: ↓ Enzyme capacity Age Group: Neonates, infants PK Result:

↓ CL ↑ t½