Pharmacology of Old Age

Question 1

What is meant by Pharmacokinetics?

Answer 1

The movement of a drug through the body

Question 2

What are the principles of pharmacokinetics?

Answer 2

Absorption
Distribution
Metabolism
Excretion

Question 3

Which is the most important principle of pharmacokinetics?

Answer 3

Metabolism, as the way young people and the elderly metabolise substances differs.

Question 4

Is age the sole factor for creating changes in medications?

Answer 4

No, must consider other factors too e.g. comorbidities which have to be comanaged.

Question 5

What are the 2 principles of absorption?

Answer 5

1. Basic environments absorb basic drugs e.g. diazepam, morphine
2. Acidic environments absorb acidic drugs e.g. aspirin

Question 6

Which drugs decrease stomach acidity and therefore, acidic drug absorption?

Answer 6

PPIs

H2 Receptor Antagonists

Question 7

What happens to body pH with increasing age?

Answer 7

Decreases, so the body environment becomes more acidic and cannot absorb basic drugs as well

Question 8

What happens to the bowels with increasing age?

Answer 8

Decreases in surface area, slowing drug absorption

Question 9

What is meant by drug distribution?

Answer 9

The proportion of free drug vs. drug bound to protein

Question 10

What are the principles distribution?

Answer 10

Basic proteins e.g. Albumin, carry acidic drugs

Acidic proteins e.g. Alpha 1 Acid Glycoprotein, carry basic drugs

Question 11

What happens to carrier proteins with increasing age?

Answer 11

Albumin levels decrease and alpha 1 acid glycoprotein levels increase meaning that basic drug remains unabsorbed in the body longer, increasing risk of delirium or confusion.

Question 12

What is meant by the volume of distribution (VoD)?

Answer 12

Theoretical volume which will contain the total amount of the administered drug at the same concentration as that of blood plasma

Question 13

What happens to the proportion of fat and muscle tissue in elderly people?
What does this mean?

Answer 13

Greater proportion of fat tissue to muscle mass.

This means that lipophilic drugs will have a higher VoD as it will be contained within the increased fatty tissue.

Question 14

In elderly patients, what does the VoD of a drug help to show in terms of drug characteristics?

Answer 14

The lipid solubility and half-life.

The higher the VoD, the higher the lipid solubility and the longer the half-life.

Question 15

What is the half-life of a drug directly proportional to?

Answer 15

The VoD of the drug

Question 16

What is the half-life of a drug inversely proportional to?

Answer 16

The hepatic/renal clearance

Question 17

Why is hepatic metabolism slowed with increasing age?

Answer 17

Decreased liver size
Illness
Decreased hepatic blood flow

Question 18

Why is renal metabolism slowed with increasing age?

Answer 18

Decreased kidney sizes.
Reduced GFR
Reduced tubular secretion
Reduced renal blood flow

Question 19

What is the problem with lipophilic drugs in the elderly?

Answer 19

If the patient undergoes cachexia, fatty tissues will break down, releasing the lipophilic protein into the body, resulting in potential delirium or confusion.

Question 20

Are hydrophilic drugs well-absorbed in the elderly?

Answer 20

Not as well as lipophilic drugs due to age-related loss of water content in the body.

Question 21

What are bio-transforming enzymes?

Do they increase/decrease with age?

Answer 21

Proteins which alter a substance.

Decrease with age.

Question 22

What is meant by pharmacodynamics?

Answer 22

How the body responds to a drug?

Question 23

What is the general principle of pharmacodynamics in the elderly?

Answer 23

A lower dose of the drug will have the SAME effect as normal dosage in a young person

Question 24

What happens to the therapeutic window with increasing age? What does this mean?

Answer 24

Therapeutic window narrows with age.

This means that toxic responses to drugs increases while therapeutic responses decrease.

Question 25

How is the therapeutic index of a drug calculated?

Answer 25

Minimum toxic dose/Minimum effective dose

Question 26

Which drugs have a low therapeutic index (<2)?

Answer 26

1. Warfarin 2. Digoxin 3. Lithium 4. Benzodiazepines

Question 27

Give an example of prophylaxis for an adverse drug effect:

Answer 27

Laxatives for opioid-induced constipation Vitamin D/Calcium for steroid-induced osteoporosis Regular blood glucose check for steroid-induced diabetes

Question 28

Give an example of adverse drug reactions that result from drug interactions:

Answer 28

Calcium slowing down Levothyroxine absorption (therefore, take levothyroxine in the morning and calcium in the evening) Beta blockers with Verapamil/Diltiazem causing bradycardia

Question 29

What is important to remember with antibiotics in the elderly?

Answer 29

They must be targeted and given in cases of definite infection. (due to increased risk of resistance, C.Diff and renal impairment)

Question 30

What are adverse effects of NSAIDs?

Answer 30

Renal impairment GI bleed Reduced diuretic effect due to increased sodium reabsorption

Question 31

What can be done to as prophylaxis for NSAID adverse effects?

Answer 31

Prescribe paracetamol for patients with mild, non-OA pain | Use less potent NSAIDs in patients with CVD e.g. Ibuprofen instead of Diclofenac

Question 32

What are adverse effects of opiates?

Answer 32

Psychomotor impairment Falls Delirium Confusion

Question 33

Why is polypharmacy important?

Answer 33

Patients more likely to suffer from adverse drug effects as multiple drugs means increased risk of interactions

Question 34

Why are over-the-counter medications important?

Answer 34

They can interact with prescribed medications

Question 35

What can be done to counteract issues in polypharmacy?

Answer 35

Prescribe 1 drug that can target 1+ problems Use combination treatments to ease pill burden Do NOT counter the adverse effect of one drug by prescribing another drug - reduce dose of initial drug or choose alternative

Question 36

Which screening tools can be used to avoid certain medications in the elderly but alert to appropriate ones?

Answer 36

``` BEER Criteria (American Geriatric Society) STOP START Tool ```