Outline the effects of critical illness on drug pharmacokinetics. Give examples.
Most candidates answered the question under the subheadings absorption, distribution,
metabolism and elimination. However, they didn’t give any details of the direction or
mechanism of change, often used vague statements without specifically addressing the
question and failed to give examples. The impact of the shock state on different kinetic
parameters including absorption from skin, tissue, muscles, enteral absorption and
inhalational was often overlooked. Similarly, the consequences of changes in volume of
distribution, protein binding (e.g. albumin and globulin, ionisation) was poorly understood
as was alteration in liver and kidney function. Although this topic is very broad candidates
were asked to only outline the details of this topic
This question is very similar to Question 5 from the first Fellowship paper of 2011. An attempt is made to answer the question and incorporate all the comments made by the college. Some mechanisms are listed, their pharmacokinetic effects are briefly outlined, and an example is offered. As the official college textbooks are useless for this topic, one should read Roberts and Hall (2013) to prepare for this question. It's paywalled, but because of the high quality of this article it would not be unreasonable for the time-poor candidate to resort to prostitution or piracy.
Boucher, Bradley A., G. Christopher Wood, and Joseph M. Swanson. "Pharmacokinetic changes in critical illness." Critical care clinics 22.2 (2006): 255-271.
Roberts, Derek J., and Richard I. Hall. "Drug absorption, distribution, metabolism and excretion considerations in critically ill adults." Expert opinion on drug metabolism & toxicology 9.9 (2013): 1067-1084.
Smith, Brian S., et al. "Introduction to drug pharmacokinetics in the critically ill patient." CHEST Journal 141.5 (2012): 1327-1336.