Limbs and Back Pharmacology

Question 1

Principles of drug use in the elderly: State the factors contributing to adverse drug reactions

Answer 1

Polypharmacy

Co-morbidities

Adherence issues

Concordance issues

Age-related body changes: Decreased renal mass, decreased muscle mass, increased MAP, increased adipocyte levels

Question 2

Principles of drug use in the elderly: State and understand the changes that occur in the aging body and how they affect pharmacokinetics etc.

Answer 2

Absorption: ↓ GI motility, ↓ absorption

Distribution: ↓ plasma bindign proteins means more available to act/toxicity, ↑ body fat and ↓ muscle mass can change distribution, ↓ CO causing ↓ perfusion

Metabolism: ↓ hepatic muscle and therefore metabolic enzymes

Excretion: ↓renal mass with decreased GFR leading to ↓ clearance

Question 3

Principles of drug use in the elderly: Identify potential adherance and concordance issues

Answer 3

• Beliefs about medications
• Polypharmacy
• Worried about possible side effects
• Forgetting to take medication
• Low manual dexterity
• Poor vision
• Impaired cognitive function

Question 4

Principles of drug use in the elderly: Changes in pharmacodynamics and homeostatic functions

Answer 4

Pharmacodynamics: Receptor sensitivity/number, hormone levels

Homeostatic function: Decreased baroreceptor reflex, thermoregulation, postural control, cognitive function and immune response

Question 5

Principles of drug use in the elderly: Key principles for prescribing in the elderly

Answer 5

• Start with low dose
• Consider non-pharmacological therapy
• Avoid starting 2 medications at the same time
• Correct dose and drug
• Lower doses, longer intervals and slower titrations

Decreased perfusion, hepatic/renal mass, gastric motility and muscle mass. Increased body fat. All affect pharmacokinetics.

Question 6

Treatment of RA: Name 4 DMARDs and their mechanism of action

Answer 6

Disease Modifiying Anti-Rheumatic drugs: Act to modify the disease, reducing progression - rather than just targeting symptoms

1. Methotrexate: Possibly functions as a folate antagonist
2. Hydroxyquinolones
3. Sulfasalazine: Possibly acts to reduce T cell function
4. Cyclosporin

Question 7

Treatment of RA: Name 4 commonly used biological agents

Answer 7

1. Inflixumab: Binds TNF-alpha
2. Ritixumab: Binds CD20
3. Anakira: Binds IL-1
4. Toculizamab: Binds IL-6

Question 8

Treatment of RA: Comment on the benefits and risks of DMARDs and biological agents

Answer 8

DMARDs: Slow to act, potentially toxic (e.g. methotrexate = teretogenic), monitoring required, mechanisms are unknown

Biological agents: Generally better than DMARDs

• Anti-TNF however does lead to increased risk of recurrent infection and SLE

Question 9

Drug use in the elderly: Outline the main pharmokinetic effects of drug use in the elderly

Answer 9