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Explore pharmacokinetic and pharmacodynamic changes in the elderly, multiple co-morbidities, polypharmacy concerns, and minimizing adverse effects for safer treatments. Learn key tips to improve medication adherence and reduce risks in this vulnerable population.
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Pharmacological Challenges in the Elderly • Pharmacokinetic changes • Pharmacodynamic changes • Multiple co-morbidities • Polypharmacy • More adverse effects • Adherence problems/cognition • Reduced diagnostic precision • Few well designed trials in this population
Pharmacokinetics in the Elderly • Absorption: remains relatively unchanged with age • Distribution: reduce in body water increase in body fat plasma protein binding • Metabolism: reduced hepatic blood flow reduced liver volume reduced enzymatic activity • Excretion: reduced renal blood flow atrophic renal tissue
Pharmacodynamic Changes • Changes in drug receptors/target organ responses - alter sensitivity to effect of drugs (> CNS effects of benzodiazepines) 2nd to neuronal loss • Impairment of secondary compensatory mechanisms - predispose to adverse effects (orthostatic hypotension with diuretics or TCAs).
Co-morbidities • Lead to polypharmacy • Increased risk of developing adverse events 2nd to co-morbidities • Risk of delirium 2nd to anticholinergic drugs 2nd to degeneration of cholinergic pathways • Increased risk of cerebrovascular events on some antipsychotics in people with pre-existing cerebrovascular damage (Shah and Shu, 2005)
Polypharmacy • Over age 65 people use an average of 8 drugs • 1/3 of those has inappropriate use of at least one drug • 10% are likely to have dangerous drug interaction (Cannon et al., 2006)
Minimising adverse effects • whenever possible, use non-pharmacological treatments • Start low, increase slowly, monitor frequently • smallest number of medications/simplest dose regimens • be familiar with drug effects in elderly • Alternative applications if difficulties swallowing tablets
Minimizing adverse events cont’d • Simple verbal/written instructions for every medication incl. generic/brand names, dosage, frequency, route and indication to avoid confusion • presenting symptoms may be a result of medications (not old age) • Avoid child-proof containers (also elder proof), use Webster pack or RDNS • Ensure carer understands treatment
Reference • Cannon, K.T., Choi, M.M., Zuniga, M.A. (2006), Potentially inappropriate use in elderly patients receiving home health care: a retrospective data analysis. American Journal of Geriatric Pharmacotherapy, 4(2), 134-143. • Shah, A., Shu, G.H., (2005). A case for judicious use of risperidone and olanzapine in BPSD. International Psychogeriatrics, 17(1), 12-22.