Prescribing in older adults |X

Question 1

What are the definitions of inappropriate prescribing (4)?

Answer 1

1. Prescribing drugs which are contraindicated
2. Prescribing a drug with an inappropriate dose or duration
3. Prescribing a drug which is likely to adversely affect prognosis
4. Failure to use a drug which could improve patient outcomes

Question 2

Why is inappropriate prescribing more common in older people?

Answer 2

1. Older people have a higher prevalence of chronic disease
2. Higher levels of polypharmacy (defined as taking 4 or more drugs) leads to an increased risk of drug-drug and drug-disease interactions
3. Age related physiological changes, such as reduced renal and hepatic function and altered body composition

Question 3

What are pharmacodynamics?

Answer 3

Pharmacodynamics are how the drug interacts with the body to produce a response e.g.when morphine binds to its receptor on a cell surface

Question 4

Ageing leads to increased (3) and decreased (3) sensitivity of the following drugs?

Answer 4

Increased:

1. Benzodiazepines
2. Opioids
3. Neuroleptics

Decreased:

1. Beta-agonist
2. Beta-blockers
3. Furosemide

Question 5

What is the definition of pharmacokinetics?

What are the 4 components?

Answer 5

Pharmacokinetics is what the body does to the drug:
It includes:
1. Absorption
2. Distribution across body compartments
3. Metabolism
4. Excretion

Question 6

How does age affect absorption of drugs?

Answer 6

Age-related changes in the gastrointestinal tract are not clinically significant as they do not affect the absorption of most drugs.

Question 7

How does age affect distribution of drugs (3)?

Answer 7

1. With ageing, total body fat increases therefore increasing the volume of distribution for fat soluble drugs.
2. Total body water however decreases, decreasing the volume of distribution of water soluble drugs.
3. Serum albumin also decreases and this increases the effects of albumin-bound drugs as the levels of unbound drug increase as a consequence.

Question 8

How does age affect metabolism of drugs (3)?

Answer 8

1. The majority of drugs are metabolised via the hepatic route.
2. Reduced liver volume and enzyme activity means that hepatic metabolism of many drugs decreases.
3. To prevent toxic accumulation doses must be reduced or dosing interval should be increased

Question 9

How does age affect excretion of drugs (3)?

Answer 9

1. Reduction in the glomerular filtration rate, GFR, is important for drugs that are excreted via the kidneys.
2. Changes in the GFR decrease the excretion of these drugs.
3. Digoxin is an example of a renally excreted drug with a narrow therapeutic index that often requires a dose reduction as we get older to prevent drug toxicity.
4. Again to prevent toxic accumulation doses must be reduced or dosing interval should be increased

Question 10

What are 4 consequences of inappropriate prescribing?

Answer 10

1. Prolong the length of hospital stays
2. Increases morbidity and mortality
3. Increase risk of adverse drug reactions
4. Poorer compliance when on multiple medications

Question 11

What is the STOPP START criteria?

Answer 11

A screening tool to aid prescribing in older people.

It consists of criteria for potentially inappropriate drugs called STOPP (Screening Tool of Older Persons’ Prescriptions)

and criteria for potentially indicated drugs called
START (Screening Tool to Alert to Right Treatment) which can aid in deciding appropriate medication

Question 12

What are some recommendations of the STOPP criteria? (there are more)

1. CVD (5)
2. CNS (3)
3. GI (3)
4. Respiratory (3)
5. MSK (2)
6. Urogenital (2)
7. Endocrine (3)
8. Falls (3)
9. Analgesics (3)
10. Duplicate drug classes (1)

Reference

Answer 12

CVD

1. Digoxin with > 125μg/day with impaired renal function
2. Non-cardioselective beta-blocker with COPD
3. Beta-blocker in combination with verapamil
4. Aspirin + PMH of ulcer disease without stomach protection
5. Aspirin, clopidogrel, dipyridamole or warfarin with concurrent bleeding disorder

CNS

1. TCAs with dementia/glaucoma/constipation/opiate/Ca channel blocker
2. Long-term neuroleptics as long-term hypnotics or in those with parkinsonism
3. Anticholinergics to treat extra-pyramidal side-effects of neuroleptic medications

GI
1. Diphenoxylate, loperamide or codeine phosphate for treatment of diarrhoea of unknown cause or severe infective gastroenteritis i.e. bloody
diarrhoea, high fever or severe systemic toxicity
2. PPI for peptic ulcer disease at full therapeutic dosage for > 8 weeks
3. Anticholinergic antispasmodic drugs with chronic constipation

Respiratory

1. Theophylline as monotherapy for COPD
2. Systemic corticosteroids instead of inhaled corticosteroids for maintenance therapy in moderate-severe COPD
3. Nebulised ipratropium with glaucoma

MSK

1. NSAID with history of peptic ulcer disease or gastrointestinal bleeding, unless with stomach protection/with moderate-severe hypertension/with heart failure/with chronic renal failure
2. Warfarin and NSAID together

Urogenital

1. Bladder antimuscarinic drugs with dementia/chronic glaucoma/chronic constipation/chronic prostatism
2. Alpha-blockers in males with frequent incontinence/with long-term urinary catheter in situ

Endocrine

1. Beta-blockers in those with diabetes mellitus and frequent hypoglycaemic episodes i.e. ≥ 1 episode per month
2. Oestrogens with a history of breast cancer or venous thromboembolism
3. Oestrogens without progestogen in patients with intact uterus

Falls

1. Benzodiazepines (sedative, may cause reduced sensorium, impair balance)
2. Long-term opiates in those with recurrent falls (risk of drowsiness, postural hypotension, vertigo).
3. First generation antihistamines (sedative, may impair sensorium).

Analgesics
1. Use of long-term powerful opiates e.g. morphine or fentanyl as first line therapy for mild-moderate pain
2. Regular opiates for more than 2 weeks in those with chronic constipation without concurrent use of laxatives
3. Long-term opiates in those with dementia unless indicated for palliative care or management of moderate/severe
chronic pain syndrome

Duplicate drug classes
1. Any regular duplicate drug class prescription e.g. 2 concurrent opiates. This excludes duplicate prescribing of drugs that may be required on a prn basis e.g. inhaled beta2 agonists (long and short acting) for asthma or COPD, and opiates for management of breakthrough pain.

Question 13

What are some recommendations of the START criteria? (there are more)

1. CVD (5)
2. CNS (2)
3. GI (2)
4. Respiratory (3)
5. MSK (3)
6. Endocrine (4)

Answer 13

CVD
1. Warfarin in the presence of chronic atrial fibrillation.
2. Aspirin in the presence of chronic atrial fibrillation, where warfarin is contraindicated.
3. Aspirin or clopidogrel with a documented history of atherosclerotic coronary, cerebral or peripheral vascular
disease in patients with sinus rhythm.
4. ACE inhibitor following acute myocardial infarction/chronic heart failure
5. Beta-blocker with chronic stable angina

CNS

1. L-DOPA in idiopathic Parkinson’s disease with definite functional impairment and resultant disability.
2. Antidepressant drug in the presence of moderate-severe depressive symptoms lasting at least three months

GI

1. Proton Pump Inhibitor with severe gastro-oesophageal acid reflux disease or peptic stricture requiring dilatation.
2. Fibre supplement for chronic, symptomatic diverticular disease with constipation

Resp
1. Regular inhaled beta 2 agonist or anticholinergic agent for mild to moderate asthma or COPD.
2. Regular inhaled corticosteroid for moderate-severe asthma or COPD, where predicted FEV1 <50%.
3. Home continuous oxygen with documented chronic type 1 respiratory failure (pO2 < 8.0kPa, pCO2 <6.5kPa) or
type 2 respiratory failure (pO2 < 8.0kPa, pCO2 > 6.5kPa)

MSK
1. Disease-modifying anti-rheumatic drug (DMARD) with active moderate-severe rheumatoid disease lasting > 12 weeks.
2. Bisphosphonates in patients taking maintenance oral corticosteroid therapy.
3. Calcium and Vitamin D supplement in patients with known osteoporosis (radiological evidence or previous
fragility fracture or acquired dorsal kyphosis).

Endocrine
1. Metformin with type 2 diabetes +/- metabolic syndrome
2. ACEI or Angiotensin Receptor Blocker in diabetes with nephropathy i.e. overt urinalysis proteinuria or
micoralbuminuria (>30mg/24 hours) +/- serum biochemical renal impairment
3. Antiplatelet therapy in diabetes mellitus if one or more co-existing major cardiovascular risk factor present (hypertension, hypercholesterolaemia, smoking history).
4. Statin therapy in diabetes mellitus if one or more co-existing major cardiovascular risk factor present.