Outline the pharmacokinetic consequences of old age. Illustrate your answer with examples.
As the general population ages, and many elderly are admitted to intensive care units and/or encountered during intensive care ward consultations, this topic is highly relevant. Unfortunately candidate performance generally lacked sufficient depth and breadth in this area. Good answers were expected to mention changes in body compartments (eg total body water, lean body mass decrease, etc), consequences of changes in organ function (eg deteriorating glomerular filtration rate, reduced liver blood flow, etc), alterations in protein levels and binding, increased likelihood of drug interactions and the influence of disease states.
Syllabus: Generic Pharmacology III2d
References: Millers’ Anaesthesia Chp 19
The college answer, while highly critical of trainees, offers little in the way of explaining what precisely was expected from them. Nor are examples offered. One might imagine that a structured answer with examples might have attracted marks. The answer below is offered in the format of [mechanism] = [consequences](example) so as to satisfy the criteria of the answer. A detailed discussion of these issues can be found in the chapter on pharmacokinetics of old age.
Absorption
Distribution
Metabolism
Elimination
Decreased dose response
Increased dose response
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