Age Changes By Sue Henderson

Pharmacokinetics How body acts on drug: Reduced renal function, resulting in reduced elimination of renally excreted drugs - toxicity Dosages should be reduced in the elderly (start low go slow) Acute illness can lead to rapid decrease in renal function

Pharmacokinetics cont… Water content of aging body decreases Fat content increases

Pharmaco-dynamics How drugs act on the body Changes in drug receptors/target organ responses - alter sensitivity to effect of drugs (> CNS effects of benzodiazepines). Impairment of secondary compensatory mechanisms - predispose to adverse effects (orthostatic hypotension with diuretics or TCAs).

Poly-pharmacy Higher rates of disease in the elderly Take many drugs > interactions/adverse effects Multiple sources (different doctors, hospitals, OTC, friends) Hoarders of meds. Medication review to confirm full list of drugs being taken

Noncompliance Unintentional - result confusion, forgetfulness Intentional - to minimise adverse effects or save money.

Minimising adverse effects whenever possible, use non-pharmacological treatments lowest feasible dose (often less than half usual adult dose) smallest number of medications/simplest dose regimens be familiar drug effects in elderly liquid medications if difficulty in swallowing Simple verbal/written instructions for every medication presenting symptoms may be a result of medications (not old age) child-proof containers (also elder proof) avoided Regular review chronic - may be possible to stop medications or reduce dose if renal function declines Make sure the carer understands treatment

References Bochner, F., Rossi, S., Royal Australasian College of General Practitioners, Pharmaceutical Society of Australia, & Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists. (2008). Australian medicines handbook (8th ed.). Adelaide: Australian Medicines Handbook.