What are simvastatin and Crestor?

Simvastatin (Zocor) and Crestor (rosuvastatin) are both in the statin family of cholesterol-reducing drugs. They both work to lower “bad” cholesterol in the bloodstream, which comes in the form of low-density lipoprotein or LDL.

Cholesterol is vital for the body to function. It’s used to provide cell structure, insulate nerve cells, enable digestion, and a host of other benefits. The body can make all the cholesterol it needs in the liver, but food also contains cholesterol that ends up in the bloodstream. There, it sticks to artery walls as a solid plaque, constricting blood flow. This can lead to debilitating or fatal heart attacks or strokes.

Statins like Zocor and Crestor lower LDL by hindering liver cells’ ability to make cholesterol. The liver manufactures cholesterol from simpler molecules. The liver has to turn these molecules into a compound called HMG-CoA reductase, which turns into cholesterol after a few more steps. Statins (also called HMG-CoA reductase inhibitors) bind with HMG-CoA reductase to stop it from turning into cholesterol.

Because the body’s natural impulse is to maintain a balanced level of cholesterol, the liver cells start to suck cholesterol out of the bloodstream, meaning it’s no longer floating around to add to arterial plaque deposits.

Statins also raise levels of HDL, the so-called “good” cholesterol. HDL molecules act as scavenger molecules in the bloodstream, binding with LDL and taking to the liver for processing. Research isn’t as clear on the mechanism by which statins raise HDL levels as it is on how the drugs lower LDL levels.

How are simvastatin and Crestor different?

Statins typically are very similar to one another, but rosuvastatin is a bit of an outlier. Rosuvastatin, aside from Lipitor (atorvastatin), is the most potent statin for lowering LDL. It’s different than simvastatin and many other statins in several important ways.

First, simvastatin is a prodrug, meaning that the chemical sold in the pill won’t lower cholesterol by itself; the body needs to break it down in the gut into a different form before it can do its job. Rosuvastatin is ready to go out of the package.

Second, simvastatin and most other statins can have bad interactions with a bunch of different drugs, whereas Crestor has relatively few.

Why? A specific system of enzymes found mostly in specialized liver cells break down simvastatin and other statins. This system is responsible for breaking down (metabolizing) all sorts of different foreign compounds, toxins, and toxic waste produced internally by our own cells. The enzyme system – created by a group of genes called CYP450 – is responsible for processing 70% to 80% of all drugs on the market.

Because different, more obscure enzymes break down rosuvastatin – enzymes only minimally involved with the powerhouse CYP450 system – Crestor doesn’t interfere as much with other drugs.

Finally, because Crestor is has a tendency to dissolve or combine with water (it’s “hydrophilic”), it has fewer muscle and nervous system side effects than simvastatin. Zocor is more likely to dissolve or combine with fats (it’s “lipophilic”), meaning it can more easily enter nerve and muscle cells to cause problems.