Geriatric drugs Flashcards

1
Q

What is the definition of polypharmacy?

A

Greater than 5 drugs/week

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2
Q

What are the two leading causes of death in ages over 65?

A

Heart disease

CA

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3
Q

What is the “prescribing cascade”?

A

Prescribing a drug, which causes an adverse effect, and prescribing another b/c you interpreted the new symptom is a new problem, rather than a side effect

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4
Q

What are the ways to prevent the prescribing cascade?

A
  • Avoid prescribing until confirm dx
  • Titrate slowly
  • Add one drug at a time
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5
Q

In is inadequate monitoring?

A

A medical problem is being treated with the correct dru, but the pt is not monitored for complications, efficacy, or both

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6
Q

What is it called when a medical problem that requires drug therapy is being treated with a less than optimal drug?

A

Inappropriate drug selection

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7
Q

What is it called when a patient is taking a drug for no medically valid reason?

A

Inappropriate treatment

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8
Q

What is Beer’s criteria?

A

List of medications likely to cause adverse effects in the elderly

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9
Q

What are the three criteria that are used in the Beers criteria?

A
  • Drugs problematic is most older pts
  • Problematic for certain diseases
  • Drugs to be used with caution
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10
Q

What are the three major physiological functions that decline with age, and are relevant to pharmacokinetics?

A
  • Glomerular filtration rate
  • Max breathing capacity
  • Cardiac index
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11
Q

What happens with weight as we age?

A

Goes down, but fat mass goes up

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12
Q

What happens to total body water with age?

A

Decreases

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13
Q

What happens to lean body mass with age?

A

Decreases

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14
Q

What happens to myocardial sensitivity to beta adrenergic stimulation?

A

Decreased

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15
Q

What happens to baroreceptor sensitivity with age?

A

Decrease

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16
Q

What happens to CO with age? TPR?

A

Lower CO

Increased TPR

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17
Q

What happens to liver size with age? Hepatic blood flow?

A

both Decrease

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18
Q

What happens to pulmonary function in general with age? Renal function?

A

Decrease

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19
Q

What are the four components of pharmacokinetics?

A

Absorption
Distribution
Metabolism
Clearance/elimination

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20
Q

What is the parameter of drug pharmacokinetics that is least affected by aging?

A

Absorption

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21
Q

Why is first pass metabolism reduced with aging?

A

Reduced liver function and blood flow

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22
Q

What is bioavailability?

A

Fraction of drug reaching the systemic circulation (IV dose = 100%)

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23
Q

What is the relative dose needed for a prodrug in the elderly? Why?

A

Increased dose d/t lower metabolism by the liver

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24
Q

What is the equation for the volume of a drug’s distribution?

A

Amount of drug in body (mg) / plasma [drug]

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25
Q

A large Vd indicates what?

A

Most of the drug is in the extravascular compartment

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26
Q

How does a lipophilic drug distribution change in the elderly? Why?

A

Increase since there is a higher fat mass and lower lean muscle mass

27
Q

What happens to the Vd in the elderly with water soluble drugs, or drugs that bind to muscle? Why?

A

Lower since elderly have lower body water and muscle content

28
Q

What is the equation for half–life of a drug?

A

t(1/2) = ln(2) x Vd/CL

29
Q

Would a highly lipid soluble drug have an increase or decrease t1/2 in an elderly patient compared to a younger patient?

A

Increased

30
Q

What happens to the t1/2 with a decreased Vd with water soluble drugs? Why?

A

Decreased Vd of water soluble drugs leads to less of an increase in half life since this tends to be balanced by a reduction in clearance by the kidneys

31
Q

What is the equation for the loading dose?

A

Vd * target [c] / bioavailability

32
Q

Would the loading dose of a highly water soluble drug be larger or smaller in an elderly pt when compared to a younger one?

A

Lower

33
Q

What happens to Vd with water soluble drugs with aging? What is the effect of this on the half life? Loading dose?

A

Lower Vd
Lower half life
Lower loading dose

34
Q

What happens to Vd with lipid soluble drugs with aging? What is the effect of this on the half life? Loading dose?

A

Higher Vd

Increased half life

Higher loading dose

35
Q

What is the equation for drug clearance?

A

CL = QxE: Q = flow rate to organ, E = extraction ratio

36
Q

What is the CL(total)?

A

CL (liver) + CL (renal) + CL (other)

37
Q

What is the extraction ratio?

A

Relative efficiency of an organ to eliminate drugs from the systemic circulation

38
Q

What are the phase I enzymes? What do these do?

A

p450s

Oxidize/reduce

39
Q

What are the phase II enzymes? What do these do?

A

Conjugation

40
Q

What is the effect of aging on phase I and II enzymes?

A

I - decrease

II - same

41
Q

What is a capacity limited drug?

A

A drug whose hepatic clearance rate-limiting step is liver enzyme function.

42
Q

What happens to clearance of a drug in the elderly if it is primarily metabolized by phase 1 enzymes? Phase 2?

A

I - decrease

II - same

43
Q

What is a flow rate limited drug?

A

A drug whose rate-limiting hepatic clearance step is flow rate

44
Q

What happens to drugs that are flow rate limited in the elderly?

A

Reduced hepatic clearance

45
Q

To keep the drug at a steady state, the maintenance rate of drug administration must equal what? What is the significance of this in the elderly?

A

The rate of clearance at the steady state

Lower maintenance doses needed, unless phase II

46
Q

How much does GFR decrease with age?

A

15-40%

47
Q

What happens to tubular secretion in polypharmacy?

A

Increases the risk of drugs competing for active transporters

48
Q

What is the substance that measures GFR?

A

Creatinine

49
Q

What is GFR?

A

sum of all filtration rates of nephrons

50
Q

What is the equation for creatinine clearance?

A

Cc = (Ucm x V) / Pcm

51
Q

Why is it that GFR in the elderly can be normal, despite reduced renal function?

A

Lower muscle mass = lower creatinine

52
Q

What is the reason for the Cockcroft and gault equation?

A

Account for creatinine differences in older people, different weights, and in different sexes

53
Q

Why do lipophilic drugs have an increase in half life in elderly pts?

A

Increased fat and increase Vd

54
Q

What happens to the volume of distribution and bioavailability of water soluble drugs in the elderly?

A

Decreased Vd

Increased plasma concentration

55
Q

What happens to the Vd and half life for lipophilic drugs in the elderly?

A

Increased

56
Q

What happens to the sensitivity to anesthetic agents in the elderly?

A

Increased

57
Q

What happens to the sensitivity to beta adrenergic agents in the elderly? Why?

A

Decreased

Beta receptors are less responsive

58
Q

What happens to the blood pressure changes in the elderly with Ca channel blockers?

A

Lower response

59
Q

NSAIDs are primarily cleared by what organs? What is the significance of this in the elderly?

A

Kidney

Lowers the kidney’s ability to compensate for the loss of nephrons in the elderly

60
Q

What is the MOA of NSAIDs?

A

Cox inhibition

61
Q

What are the elderly susceptible to with NSAIDs? Why?

A

Renal damage

Loss of the kidney’s ability to compensate for the loss of nephrons in the elderly

62
Q

What are the major side effects of anticholinergic agents in the elderly?

A
Hypotension
Blurred vision (both lead to falls)
63
Q

What are the meds that have high anticholinergic properties? (11)

A
Anticonvulsants
Antidepressants (TCAs)
Antihistamines
Antipsychotics
Cardio
GI antispasmodics
H2 antagonists
Muscle relaxants
Parkinson
Urinary antispasmodics
Vertigo
64
Q

What happens to the rate of first pass extraction in the elderly? How does this relate to the bioavailability of the drug?

A

Decreases

Increased bioavailability