How Drugs Work: An Introduction

The first How Drugs Work post of the series is just going to explain the basics of drug interactions, so that for the rest of the series, you’ll all know what I’m talking about when I’m comparing receptors to giant cuddly teddy bears with capes, or other such lunacy. 

Now, it could just be me being a massive nerd here, but I LOVE finding out about how a drug works before I take it. It’s incredible to think of it in your body, to understand how it affects you and your system, and how that makes you feel. To understand how an individual drug works, it helps to have a bit of background about pharmacology.

The basic principle of pharmacology is that all drugs must cause their effect by exerting some chemical influence on a cell or on something within a cell. This sounds obvious but actually it took a surprisingly long time for this truth to be accepted and in some circles, it’s still not quite made it. So, for any drug of interest, you can assume that it attaches itself to something within a cell or on a cell, and that in doing so it causes a chain of events that lead to the overall drug effect. For example a painkiller binds to a specific molecule and triggers changes in the cell that stop you  feeling pain. In many cases, through the brilliance of science, we actually know what molecule the drug binds to, and how this causes an effect.

Aspirin (in yellow), clinging tightly to a COX-2 enzyme
Image credit.

One of the most common things for drugs to bind to are proteins, and the proteins that tend to be targets for drugs can be broadly classified into enzymes (biological catalysts), carrier molecules, ion channels (allowing charged molecules to move in and out of a cell) and receptors. There are always exceptions, of course. When I was a child I used to imagine that my body was full of really teeny tiny little people, scampering around, sending messages, moving stuff back and forth, pumping my heart, inflating my lungs and generally keeping things running smoothly. As weird as this may sound, it’s not an unhelpful analogy. Okay, we are not full of teeny tiny magic people, but we are full of teeny tiny amazing molecules doing the jobs that I once imagined little sparkly wizards were doing. Molecules run your cells, and therefore your body. The biochemical system that  you are built from, and that keeps you alive, is a thing of deep, intricate complexity, and more than that, it is a thing of wonder. If it truly was run by tiny wizard people, they’d certainly be the world’s most efficient and impressive multi-taskers.

So to try and modify this highly evolved, complex, beautiful system is a huge challenge. Not least because even with decades of research behind us, we don’t understand everything about molecular biology, and how our cells run. We certainly don’t understand everything about how things go wrong, how disease can change the system. The multi-tasking nature of that system makes trying to change it a delicate and dangerous process. There are natural molecules that can have effects on your body; caffeine for example, or alcohol, to name two. But most drugs that you take have been designed, carefully, chemically, to fit a specific molecule, to enter your perfectly balanced system and make a tiny calculated change that will have a greater overall effect. It might stop the molecule doing its job wrong, it might stop it doing it altogether. It might speed up a reaction, or slow it down. Whatever it is doing, the fact that we can do this, we have evolved enough to design chemicals that can help our bodies work is… magical. Except it isn’t magic, it’s science.

This is what I want to show you with this series of posts; how amazing it is that drugs that people designed can enter your cells and make minuscule changes. How those changes can have wider effects. How stunning and impressive this science of pharmacology is. I hope you come along to find out more.

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