Steroids. I’m taking one right now, prednisone (Deltasone / Rayos; thanks, memory palace!) because I’ve been sick for two weeks. So what are steroids, what do they do, and how does prednisone work? Let’s dive in.
What I do know is that steroids are lipid-based; they have that cyclic four-ringed structure and are related to cholesterol, which is a type of sterol, which are related to steroids. Steroids do two things: they are a part of cell membranes (I remember cholesterol also being a part of cell membranes) and act as signaling molecules, I believe as hormones. The adrenal cortex houses several lipid-based steroids, in a general class called corticosteroids: aldosterone, which is a mineralocorticoid (it increases blood pressure), and the three Cs, the glucocorticoids: cortisol (often known as the stress hormone), corticosterone, and cortisone. The glucocorticoids speed up gluconeogenesis, the creation of glucose from non-carbohydrate precursors, are anti-inflammatory in nature and suppress the immune response. So what about prednisone?
Prednisone, a glucocorticoid, was patented only in 1954 and is the 27th most commonly prescribed medication in the US. It’s mainly used to suppress the immune system and decrease inflammation. Okay, so that tracks with the three Cs. Prednisone is taken orally and is a prodrug that is converted to prednisolone by the liver before it becomes active. That’s interesting because I’ve been prescribed prednisolone (139th most prescribed) also. Prednisone is used to treat respiratory issues such as asthma and COPD. So, prednisone by itself does nothing; it’s a prodrug. It has to be converted/metabolized in the liver to prednisolone, so we need to look at the pharmacology there.
So prednisolone is lipophilic and can pass through cell membranes easily. Because steroids are lipids, they love fat, are uncharged and non-polar and mesh well with the C-H bonds of the cell membranes. They enter and bind to the glucocorticoid receptor (GCR) in the cytoplasm. I can’t find exactly where it’s located; I think it’s just sort of floating around. Once it binds, the end result is the synthesis of anti-inflammatory proteins and a block of transcription of inflammatory genes. Neat. So in terms of asthma, steroids reduce the inflammation of inflamed airways. My nose and throat are irritated and inflamed and the steroid is helping that. Double neat.
So what are other kinds of steroid medications? Well of the top 75 commonly prescribed, along with prednisone at #27, we have fluticasone (Flonase) at #18, which is a glucocorticoid and budesonide/formoterol (Symbicort) at #57, which is another glucocorticoid. And an honorable mention goes out to dexamethasone (Decadron) at #272, which is also a glucocorticoid that made me vomit when I had my wisdom teeth taken out. So there you have it. Steroids: quick and dirty.
Wait, but what about NSAIDs!? Non-steroidal anti-inflammatory drugs? That’s for another blog!