Prescribing for the elderly

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Prescribing for the elderly

• T. Walley
• SH Khoo

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Drug Use in the Elderly Common

• 70 of pts over 65 taking medication regularly
• CVS 32
• Musculoskeletal 10
• GIT 8
• Respiratory 7
• Compliance high (75)

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But often poor in quality

• 36 of hypnotics at greater than recommended
  doses
• Potentially harmful interactions in 28
• Duplication 4
• Appropriateness of many of the other drugs?
• Mostly (80) repeat prescribing ( little review)

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Prescribing Rates increasingno of prescription
per head per year
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Why increasing rates?

• Less therapeutic nihilism about elderly e.g.
  hypertension
• Better evidence of effect in the elderly
• Increase in numbers of elderly and very elderly
• Increasing patient demand perhaps?
• Defensive behaviour by doctors?

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Problems with Prescribing for the elderly

• 10 of hospital admissions of elderly due to
  Adverse drug reactions
• Inappropriate prescribing accounts for about 50
  of these.
• Large numbers of less severe adverse drug
  reactions, prompting GP visits, or poor
  compliance with therapy

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Reasons for poor prescribing in elderly

• Excessive response to symptoms
• Demand (real or perceived)
• Inappropriate response to nonmedical problems
• Unrealistic expectations on part of patient or
  doctor
• Prescribing by rule and not individualising
• Inadequate review failure to discontinue drugs
  (hospital v primary care)

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Incremental prescribing Example
Dyspepsia Rx ranitidine
BP? Rx nifedipine
More dyspepsia and so on
Ankle swelling Rx diuretic
Ankles still swollen, low K Increase does of
diuretic, add Ksupplements
Gout Rx diclofenac, allopurinol
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Clinical Pharmacology in the elderly

• Pharmacokinetic differences
• Drug absorption unchanged
• Decreased renal clearance of many drugs (Li,
  gentamicin, digoxin)
• Hepatic clearance decreased (sufficient reserve
  for this to only be a problem rarely, except
  perhaps decreased first pass metabolism of many
  drugs)
• Different water/fat ratios - higher plasma
  concentrations of some (water soluble) drugs (eg
  digoxin)

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Clinical Pharmacology in the elderly

• Pharmacodynamic differences
• Increased susceptibility to some drug effects
  despite similar plasma concentrations eg
  benzodiazepines, antihypertensives
• ?Alterations in receptor density in some cases
• Decreased homeostatic reserves e.g. postural
  hypotension

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Clinical Pharmacology in the elderly

• Comorbidities
• Other drug therapies and interactions more likely
• Adverse drug reactions more common in elderly
  than in younger patients

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Studying Drugs in the Eldelry

• In the past it was not necessary to test a drug
  in elderly even though they were likely to be
  major users
• eg benoxaprofen withdrawn NSAID caused
  hepatotoxicity and photosensitivity in elderly
  but not in younger trial subjects
• Importance of reporting adverse drug reactions

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Compliance/Adherence/Concordance

• Will the patient take the tablets?
• Many elderly deterred by
• Adverse effects
• Complex regimens with multiple drugs
• Poor information (written better than verbal)
• Confusion between hospital and primary care
• Intelligent non-compliance

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Residential and Nursing Home Patients

• Very high levels of drug use
• For whose benefit? Patient or staff?
• eg hypnotics, psychotropics
• Drugs continues when original indication long
  passed inadequate review

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Key Principles for Prescribing in the Elderly (or
anyone else)

• Careful clinical assessment
• Of all the patients problems, not symptom by
  symptom
• If in doubt, dont prescribe
• Start with low doses
• Increase in small increments
• Keep regimens simple
• Avoid polypharmacy as much as possible