Pharmacology and Older People

Question 1

Absorption:
What is it measured in terms of? What does this mean?

What is it affected by?

Distribution:
What does Vd stand for?

In the elderly, what changes affect this?

How does the Vd change for Lipophilic and Hydrophilic drugs? Give examples of drugs

How do Plasma Albumin levels change? What’s the affect?

Metabolism:
How is it affected with age?

Elimination:
What’s it measured by?

How is it affected with age?

Answer 1

• Bioavailability (F) - Fraction of drug reaching blood
• Food, Co-administered medication, and Comorbidities e.g. Dysphagia

• Volume of Distribution
• Increased body fat, Decreased body water, and Lean body mass
• • ↑Vd of Lipophilic drugs (Benzodiazepines, Barbiturates)
  • ↓Vd of Hydrophilic drugs (Ethanol, Lithium)
• ↓Albumin reduces the amount of albumin-bound drugs e.g. Benzodiazepines

• ↓Liver mass and Hepatic blood flow

• Half-life and Clearance (volume of serum from which drug is removed per unit of time)
• ↓Kidney size, Renal blood flow, Nephrons, GFR

Question 2

Pharmacodynamics:
How is it affected with age?

Why are older people more at risk of cognitive effects from drugs?

Answer 2

• • Increased sensitivity to sedation and psychomotor impairment
  • Increased intensity and duration of effects of morphine/opiates
  • Increased cardiac sensitivity to digoxin
• Increased permeability of BBB

Question 3

What is Beer’s criteria?

What other criteria is used for appropriate medication use?

What are Common Side-effects?

Answer 3

• List of medications deemed inappropriate for older patients due to unacceptable side effects of more appropriate alternatives
• STOPP START criteria
• • Can be due to drug/illness e.g. Postural hypotension
  • Many drugs can cause similar side-effects

Question 4

Polypharmacy:
What is it?

What is the Prescribing Cascade?

Adverse Drug Reactions:
What are the risk factors for it?

Drug Interactions:
What 2 drug types commonly interact?

What the common side-effects due to the interactions?

Compliance:
What is it affected by?

How is it improved?

Answer 4

• > 5 medications
• Prescribing medicine to prevent side effects of other

• Polypharmacy, Multi-morbidity, Previous adverse reactions, Low BMI (Sarcopenia), Elderly, Renal impairment, Compliance

• Cardiovascular and Psychotropic drugs
• Confusion, Cognitive impairment, Hypotension, AKI

• Cognitive impairment, Visual impairment, Manual dexterity
• Communication, simplification of regimes, labelling, packaging, Dossett bottles/Bottles, engaging carers, recognition of side-effects