Introduction from David Nutt
As many of you will know I am a psychiatrist with a special interest in psychopharmacology. From the very beginning of my scientific and medical training I have been fascinated by the way in which drugs work and the power they have to change human health. For the past 35 years I have been actively researching the mechanisms of drug effects in the brain and during this time have done a large amount of teaching on this topic, to medical students, nurses, science students and psychiatrists. It is this teaching experience that has led to the production of the VPM app. It derives from this experience and a series of books and other publications that I have produced to try to demonstrate the explanatory power of pharmacology and the delight that this gives me.
I hope you agree that this is a useful and engaging way to present what can be a complex set of data and that this app helps you in your learning, and if you are a practicing clinician, in treating patients.
How we can visualize drugs
Pharmacology in its simplest form is a straightforward topic. Drugs are (usually) small molecules that interact with specialised proteins located on the outside of cells that are either receptors or transporters (reuptake sites). These are the essential processes that neurotransmitters and hormones use to regulate the body’s physiology, and drugs modulate these endogenous processes. In some cases drugs interact with enzymes that are responsible for the synthesis or degradation of neurotransmitters or with ion channels that regulate the passage of charged ions across cells membranes. Thus in the brain/CNS drugs not only modulate neurotransmitter function to produce therapeutic benefits but also give us insights into the way in which the brain works – since neurotransmitters are the key elements in providing the complexity and sophistication that is brain function. But also drugs have unwanted or adverse effects and these too can largely be understood in terms of pharmacology.
During my years of teaching pharmacology it has become more and more evident that many students find the topic more difficult than it should be and in the case of clinicians this limits the way in which they practice medicine through less than optimal prescribing. A significant aspect of the difficulties students have is in terms of the terminology that is used to explain drug actions and particularly to define drug classes. When they ask why the nomenclature is so inconsistent I explain that there has beenno international organization tasked with producing a logical set of definitions and acronyms so they have been made up in a random way as new drugs have emerged into clinical usage.
This app is designed to use the approach I have found most useful over the years in educating about pharmacology – visualisation of interactions. It builds on the fact that almost all drug effects can be defined by the drug binding to one of the 4 sorts of proteins – receptors– transporters – enzymes – ion channels. Specificity is provided by the particular neurotransmitter that also engages with these targets and by whether the drug enhances or blocks the actions of this neurotransmitter.
How to use the library
Working with my colleague Dr Sue Wilson, we have used a new set of pleasing and visually clear graphics to produce a unique image for each drug. The medicines in the library are described by Mode of Action (transporter, receptor, enzyme, ion channel) and by whether they have one action (mono) or more than one (multi). They are then illustrated by mechanism (eg receptor antagonist, uptake inhibitor) and by target (eg dopamine, noradrenaline). The most important neurotransmitter actions are shown with solid lines and those which may be considered as secondary or less important with dotted lines. In addition we have included data on the uses of the drug (efficacy) (both officially approved indications and those for which there is evidence to support its use, for example well-referenced expert guidelines). We have also included the major or most important adverse effects.
How this fits with other classifications
Over the last few years 5 major international scientific organisations have been working together to produce a rational nomenclature for psychiatric drugs based on neuroscience (Neuroscience-based Nomenclature, NbN). This has now been published and information is available at http://nbnomenclature.org/. Sue and I are key members of that working group which is continuing to update and add to its outputs, and we have done our best to ensure that VPM content meshes with the content and data of NbN.