 Welcome back to our MedSmarter question of the week where we're taking a smarter approach to preparing future physicians. Before we get started, if you'll take just a quick minute and click that like button and also subscribe and turn the bell on so that you'll be notified when we post new videos. Let's get right to that question. As always, let's start with the last sentence and then read the rest of it yet. Which of the following mechanism describes the action of a torvastatin in reducing serum levels of LDL cholesterol? So that actually seems to be mostly all of it contained in this specific question. I'm going to go back and read the rest just to see if there's anything they give us that might help us to answer this question. But this sounds like it's going to be more of just a pure knowledge question. A 47 year old woman with diabetes mellitus receives the results of a fasting lipid profile that reveals hypercholesterolemia to reduce the patient's mortality risk. His physician recommends lifestyle changes and initiates therapy with a torvastatin. Which of the following mechanism describes the action of a torvastatin in reducing serum levels of LDL cholesterol? So this is purely a question of this last sentence is all you need for this question. So they're given a torvastatin. How does it work? So first and foremost, what is a torvastatin? A torvastatin is the generic name for Lipitor which is a cholesterol lowering medication. Which is a statin. It's a HMG Coase reductase inhibitor. So let's look at these answer choices. Come up with your answer right in the comment box below. So let's look here. A positive feedback to increase three hydroxy, three methyl, glutaral, coenzyme A lyase activity. All right. Three hydroxy, three methyl, utero, coenzyme A lyase activity. Well that's our HMG Coase, but we need to make sure we're looking here because the lyase that might be something trying to throw us off. I don't believe that HMG Coase is a lyase. I think it's more of a reductase. So I'm going to leave this in because this is HMG Coase, but I think this is not the correct type of activity that we have going on. B, competitive inhibition of three hydroxy, three methyl, glutaral, coenzyme A reductase. I just mentioned I think it's a reductase inhibitor, which is what follows with this. So I'm thinking B might be my answer, but I'm going to keep looking. An activation of the three hydroxy, three methyl, glutaral, coenzyme A synthase. Synthase doesn't seem to be what I'm looking for. I think I'm looking for the reductase inhibitor, not an inactivator. So I'm going to mark out C. D, negative feedback to decrease thylase activity. That is not the function of a statin, so I'm not going to worry with that. And then E, non-competitive inhibition of citrate synthase. Citrate synthase, that's something in the Krebs cycle. That is not an HMG Coase reductase inhibitor, which is a torvostatin, we know. So I'm down to either the HMG CoA Liase activity or reductase inhibition. And I do remember statins are HMG CoA reductase inhibitors, which follows everything that option B gives me. Therefore I'm going to make B my final answer. And B is the correct answer. So like we said, this three hydroxy, three methyl, glutaral, coenzyme A reductase inhibition is HMG CoA reductase. This is what catalyzes our rate-limiting step in synthesizing cholesterol. If we can block that off, we can decrease the synthesis of cholesterol. So that enzyme will convert the HMG CoA into mevalonic acid, which is the precursor to cholesterol, right? So blocking that, blocking cholesterol production because we don't have the mevalonate. Now one further thing we need to know about this. When do we start statin in patients? Well this particular patient has diabetes mellitus, so is therefore considered a risk factor for heart disease. So at that point in time, we will initiate therapy when our LDL levels are greater than 130. So LDL greater than 130, we initiate pharmacotherapy in patients that have risk factors. And our goal for the LDL is to get it to less than 100. Okay, and that's milligrams per deciliter. If you found this material helpful for your studying, please like and consider subscribing to the channel. Also share this video so that more people can benefit from it like you have.