Geriatric Pharmacology ARS Session

Question 1

Geriatric patients make up ___ of the population and yet receive ___ of prescription drugs

Answer 1

13% of population taking 30% of the total prescription drugs

Question 2

1 take home from this lecture

Answer 2

D/C the amytriptyline

Question 3

What does not change much with advancing age?

Answer 3

Absorption - bioavailability does not change, but peak serum concentrations may be lower or delayed

Question 4

Exceptions to which drugs aren’t as bioavailable in older people

Answer 4

Drugs with extensive first-pass effect - eg nitrates so serum concentration may be higher because less drug is extracted by a smaller liver

Question 5

Factors that affect drug absorption

Answer 5

• Food taken with the drug (SA carbidopa/levodopa)
• Comorbid illness (diabetic gastroparesis)
• Enteral feedings (phenytoin)
• Drugs that increase gastric pH or affect GI motility may affect absorption ( PPIs and iron)

Question 6

Hypertensive woman is switched from atenolol to propanolol - becomes despondent and confused. This is due to what?

Answer 6

Lipophilia

Question 7

Effects of aging on VD

Answer 7

• Decreased body water –> lower VD for hydrophilic drugs
• Decreased lean body mass –> lower VD for drugs that bind to muscle
• Increased fat stores –> higher VD for lipophilic drugs and lipid soluble more likely to get into brain
• Decreased plasma protein –> higher % of drug that is unbound

Question 8

Aging and metabolism

Answer 8

• Liver is most common site of drug metabolism

- Metabolic clearance of drug by liver may be reduced because of decreased flow, size etc

Question 9

Phase I vs Phase II metabolism in aging

Answer 9

Phase I - convert drugs to metabolites
Phase II - pathways convert drugs to inactive metabolites that do not accumulate

Drugs metabolized by phase II is preferred/safer for older patients

Recall: The Old Liver

Question 10

Which pharmacokinetic factor changes accounts for most change in drug effects with age

Answer 10

Elimination

Question 11

Since you have to use Cockroft-Gault… what kind of rough estimate can you use to estimate aging effects on renal function?

Answer 11

10 ml/decade decline

Question 12

With ___ age and ___ body weight, the serum creatinine becomes less reliable

Answer 12

advancing age, decreasing body weight

Question 13

How come serum creatinine does not reflect creatinine clearance?

Answer 13

Decreased lean body mass means less creatinine made, and therefore less to clear

Question 14

Pharmacodynamics

Answer 14

What the drug does to the body

Question 15

Pharmacokinetics

Answer 15

What the body does to the drug

Question 16

Why are elderly at greater risk for bleeding at any given INR?

Answer 16

They have additional problems that increase the risk (friable stomach, more likely to fall & suffer head trauma)

Question 17

Adverse Drug Event

Answer 17

Any noxious, unintended and undesired effect of a drug, excluding therapeutic failures, poisoning or abuse

Question 18

Most common cause of adverse drug reactions in the elderly is:

Answer 18

Number of medications prescribed

Question 19

What percent of ambulatory older adults receive at least one potentially inappropriate drug?

Answer 19

20%

Question 20

Sphincter that controls the bladder is under what kind of control?

Answer 20

Alpha 1 adrenergic

To hold it, you gotta inhibit parasympathetic

Question 21

When to be cautious about medication withdrawal

Answer 21

• Sudden cessation of amytriptyline may cause a cholinergic rebound syndrome (agitation, borborygmi diarrhea)
• Sudden withdrawal of clonidine may cause rebound hypertension but less likely with dose less than 1 mg daily

Question 22

What kinds of drugs can induce parkinsonism

Answer 22

Metoclopramide, valproic acid, prochlorperazine

Question 23

Why is digoxin no longer a geriatric staple

Answer 23

Absence of LV systolic dysfunction or Afib with RVR means dig can be d/c

In aFib with RVR, slows rate at rest but not with exertion

We have better drugs.

Question 24

RR, AR, or NNT?

Answer 24

AR reduction and NNT are the most important things when deciding whether or not to give someone a drug.

Question 25

Parsimony

Answer 25

Prescribe as few drugs as possible

Question 26

Look at definitions of ARR and RRR

Answer 26

RRR: (incidence control- incidence Rx)/
incidence control

ARR: (incidence control-incidence Rx)

NNT: 100/ARR

Question 27

Silo thinking

Answer 27

“Silo thinking”: failure to account for impact of multiple chronic diseases on medication efficacy and safety

Question 28

Deprescribing

Answer 28

Deprescribing is the process of tapering or stopping drugs, aimed at minimizing polypharmacy and improving patient outcomes

Question 29

Principles of management of elderly with multiple chronic diseases

Answer 29

• Choose treatments that have clinical impact within life expectancy of patient and fewest adverse effects
• Choose treatments that may have benefit for more than one chronic disease