Table of Contents

The intracellular organelles are minor players on the stage of Intensive Care Medicine, and it is no wonder that the college has never raised these in a question (outside of the example of mitochondria). For some nighmarish future scenario where the ICU trainee might be asked an exam question on this topic, this chapter offers short notes on what the organelles do, and what they are supposed to look like. Particular emphasis is placed upon the possibility that labelled diagrams might one day be asked for. The possibility of this is quite remote, and one can safely skim over this section, expecting never to be questioned on the structure or function of the Golgi apparatus.

This chapter answers parts from Section B(c) of the Primary Syllabus; "Describe isomerism and provide examples". At the time of writing, this chapter represents the only pharmaceutics question ever asked in the Primary written paper, this being Question 20 from the second paper of 2012.  "Explain the clinical relevance of enantiomerism"and "give a clinically relevant example" seems to be the entire expectations from the college regarding this topic. 

The cytosol is a weird fluid which is so packed with protein and other macromolecules that their bulk produces a sieving effect which delays diffusion, and yet it maintains a viscosity close to that of water. Its water contents is mainly adsorbed onto proteins as a hydrating layer, which is essential for their function. Variations in chemical and physical properties of the cytosol differ between cells and between even regions within the same cell.

An adverse drug event occurs during drug therapy but does not necessarily have any causal relationship with the drug, whereas an adverse drug reaction is directly related to the drug and occurs in the course of its appropriate use.

Interactions between drugs can be classified as pharmacokinetic and pharmacodynamic. Pharmacodynamic drug-drug interactions are briefly described in another chapter. Here, the focus is on the mechanisms by which drugs interfere with each other's absorption, distribution, metabolism and elimination.

Interactions between drugs can be classified as pharmacokinetic or pharmacodynamic. The pharmacodynamic interactions of drug-on-drug can be divided into three broad groups: interference with drug effects on receptor function, interference with a physiological control process, and additive or opposing physiological effects. To elaborate on these is the objective of this chapter.

Human populations express significant genetic polymorphism. This polymorphism extends to drug receptor targets, secondary messenger system and other homeostatic or regulatory pathways. Pharmacogenetics is the study of variability in drug response due to these inherited features. Examples of pharmacogenetic disorders include malignant hyperthermia,  G6PD, porphyria and atypical plasma cholinesterase.

Human populations express significant genetic polymorphism. This polymorphism extends to drug receptor targets, secondary messenger system and other homeostatic or regulatory pathways. Pharmacogenetics is the study of variability in drug response due to these inherited features. Examples of pharmacogenetic disorders include malignant hyperthermia,  G6PD, porphyria and atypical plasma cholinesterase.

In summary, one can say that infants and neonates are slow to absorb, slow to metabolise and slow to excrete all drugs, and that this gradually changes to more adult-like levels over the course of the first year of life. Pharmacodynamic alterations can be generally summarised as "more sensitive to everything". 

Toxicology of childhood differs from adult toxicology on several key issues. In both scenarios, the patient is frequently uncooperative and history is often cluded, leading to empirical decisionmaking. In children, the situation is complicated by their tendency to compensate readily up to a certain cliff's edge, and then to collapse in a spectacular manner. Most of the routine toxicological primary survey is valid in the paediatric setting.

This chapter answers parts from Section D(iii) of the 2017 CICM Primary Syllabus, which expects the exam candidate to "describe alterations to drug response due to physiological change, with particular reference to ...