Pharmacotherapy in Elderly

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Patients older than 65 years represent approximately 14% of the population in the Czech republic.[1] Aging brings with it quite a few changes, some of which have implications for treatment.

  • polymorbidity - greater number of diseases requiring greater number of drugs
  • polypharmacy - the use of large quantities of drugs (4 or more), incorrect combinations of drugs or prescription non indicated drugs
  • underprescription - nonprescription drugs that have a demonstrable effect on the disease and survival (typically statins, β-blockers after AMI, cholinesterase inhibitors in Alzheimer's dementia, sufficient analgoterapie in cancer patients, antidepressants)
  • decreased compliance - due to dementia or just due to excessive amounts of drugs

Changes in Pharmacokinetics[edit | edit source]

Absorption Decrease[edit | edit source]

There is pH increase in stomach, atrophy of villi and mucous in gut (decrease resorptive area), decrease in blood flow and motility in the GI tract. Overall, this leads to a slower onset of action of drugs administered orally. Muscle atrophy and reduced blood flow to the periphery is involved in the delayed onset of action of medications given intramuscularly.

Distribution[edit | edit source]

There is physiological decrease of total body water, it can be enhanced by dehydration (typical for the elderly). Dehydration affects the drugs that are water-soluble. Their concentration in plasma is increased and toxic.

On the contrary, the concentration of drug fat-soluble increases due to higher total body fat (drugs are stored in adipose tissue) → benzodiazepines.

Malnutrition contributes to decrease in serum albumin - by increasing the plasma free fraction of drugs that bind to albumin → PAD, antidepressants, beta blockers.

Decreased Metabolization and Excretion[edit | edit source]

  • Due to the decrease in total liver weight and liver perfusion, reduced function of some enzymes (CYP, glucuronyltranspherase → benzodiazepines).
  • Decreased glomerular filtration, renal clearance, tubular secretion, renal hypoperfusion → aminoglycosides, lithium, digoxin, cimetidine, allopurinol, a contrast agent.

Changes in Pharmacodynamics[edit | edit source]

  • increased number of receptors or sensitivity to drugs (warfarin, heparin).[1]
  • increased sensitivity to adverse effects of digoxin.[1]
  • increased CNS sensitivity to benzodiazepines, morphine, which cause sedation, delirium, depression, or even at therapeutic doses.[1]
  • numbness receptor beta - reduced effectiveness of β-blockers.[1]

Adverse Effects and Drug Interactions[edit | edit source]

Side effects of drugs occur up to 20% of deaths in the elderly.

Typical side effects in the elderly are:

  • orthostatic hypotension (syncope, falls)
  • diarrhea, constipation
  • sedation, delirium, confusion

Often drug interactions:

  • warfarin + sulfonamides → displacement of drug from binding to binding protein → higher free fraction of warfarin and the risk of bleeding

Unsuitable/less Suitable Drugs in the Elderly[edit | edit source]

  • tricyclic antidepressants - anticholinergic effect
  • antispasmodics - the risk of urinary retention, delirium
  • barbiturates, benzodiazepines - the risk of sedation, addiction
  • methyldopa - depression, sedation, bradycardia
  • digoxin - possible high risk of adverse effects

Medical drugs which need smaller doses (evidence based)[1]:

  • atorvastatin (standard 10 mg/day, in elderly 5 mg/day)
  • ibuprofen (standard 400-800 mg/3-4x day, in elderly 200 mg/3-4x day)
  • metoprolol (standard 100 mg/day, in elderly 50 mg/day)
  • omeprazole (standard 20 mg/day, in elderly 10 mg/day)
  • and more ...

Links[edit | edit source]

Related Articles[edit | edit source]

Sources[edit | edit source]

References[edit | edit source]

  1. a b c d e f TOPINKOVÁ, Eva, et al. Geriatrie : Doporučený diagnostický a léčebný postup pro všeobecné praktické lékaře [online] 1. edition. 2007. Available from <>. ISBN 80-86998-XX-X.