Zocor (simvastatin) vs. Crestor (rosuvastatin)

Zocor (simvastatin) and Crestor (rosuvastatin) are both members of the family of cholesterol-lowering drugs called statins, which revolutionized the management of cardiovascular diseases, many of which are caused by cholesterol plaque deposits in the arteries.

Crestor is the more potent cholesterol-lowering drug, and it's also newer than Zocor.

Both simvastatin and rosuvastatin have similar side effects, including headache, nausea, vomiting, diarrhea, and muscle pain. Rarely, both drugs may cause liver, muscle, and kidney damage.

Aside from being better at lowering so-called "bad" cholesterol levels in the bloodstream, another advantage to rosuvastatin is that it has far fewer negative interactions with other medications than simvastatin, or most other statins, for that matter.

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.

• Simvastatin and rosuvastatin are used for reducing total cholesterol, LDL cholesterol, and triglycerides, and for increasing HDL cholesterol.
• In patients with coronary heart disease, diabetes, peripheral vascular disease, or history of stroke or other cerebrovascular disease, Zocor and Crestor are prescribed for reducing the risk of mortality by reducing death from coronary heart disease, reducing nonfatal myocardial infarction (heart attack) and stroke, and reducing the need for coronary and noncoronary revascularization procedures.

The potential side effects of both Zocor and Crestor are nearly identical and are similar to those seen in other statins. The most common side effects include headache, nausea, vomiting, diarrhea, and muscle pain. Rarely, forgetfulness and memory loss can happen with both these medications.

Doctors' chief worries when prescribing patients simvastatin and rosuvastatin are potential liver damage and muscle breakdown. Though serious liver damage is rare, doctors prescribing either Crestor or Zocor will closely monitor important chemical markers that show up in liver tests to make sure the levels are in the acceptable range. Abnormal liver tests usually return to normal after shortly after dosing starts, but if chemical markers remain three times higher than the normal accepted highest levels, your doctor will discontinue administering the medications.

Muscle breakdown is also a serious problem. If statins cause the muscle protein myoglobin to leech into the bloodstream, it can shut down the kidneys, which aren't equipped to filter out that protein. That condition is called rhabdomyolysis, and can be potentially fatal.

Also, statins like Zocor and Crestor can cause spikes in blood sugar the mirror conditions like those seen in diabetes.

This isn't a full list of side effects. Consult your doctor for more information if you're taking either of these drugs.

simvastatin

• The recommended dose range of simvastatin is 10 mg to 40 mg, and it is administered once daily in the evening with or without food. Therapy usually is initiated with 10 or 20 mg daily, but individuals who have a high risk of heart disease can be started on 40 mg daily.
• Simvastatin 80 mg is restricted to patients who have been taking simvastatin 80 mg chronically (for example, for 12 months or more) without evidence of muscle toxicity because the 80 mg dose is associated with increased risk of muscle toxicity, including rhabdomyolysis. Patients who are currently tolerating the 80 mg dose of simvastatin who need to start an interacting drug that should not be taken with simvastatin or is associated with a dose cap for simvastatin should be switched to an alternative statin or statin-based regimen with less potential for the drug-drug interaction.
• Patients that require more than the 40 mg dose should be switched to an alternative drug.

Crestor

• The starting dose for most adults is 5 mg once daily.
• The maximum dose is 40 mg daily, and this dose should be reserved for patients who do not adequately respond to a 20 mg dose.

As mentioned earlier, rosuvastatin has far fewer harmful drug interactions that Zocor and other statins. Still, Crestor is not without dangers. Cyclosporine can exponentially increase rosuvastatin levels in the blood, increasing the chances of side effects. Also, you shouldn't take the blood thinner warfarin (Coumadin) with Crestor, nor should you combine it with drugs that could damage the liver, like nicotinic acid or gemfibrozil (Lopid).

Antacids reduce the body's ability to absorb Crestor, so don't take them within two hours of a dose of rosuvastatin.

Zocor, on the other hand, is similar to other statins in that is has a high number of adverse interactions with other drugs.

A number of drugs make it more difficult for the body to break down and get rid of Zocor, which can make simvastatin more toxic to muscle tissue. Some of these drugs include:

• erythromycin (E-Mycin),
• ketoconazole (Nizoral),
• itraconazole (Sporanox),
• clarithromycin (Biaxin),
• telithromycin (Ketek),
• cyclosporine (Sandimmune),
• nefazodone (Serzone),
• boceprevir (Victrelis),
• telaprevir (incivek),
• voriconazole (Vfend),
• posaconazole (Noxafil), and
• HIV protease inhibitors such as:
  • indinavir (Crixivan) and
  • ritonavir (Norvir).

Other drugs that you shouldn't take with simvastatin include:

• Amiodarone (Cordarone),
• verapamil (Calan Verelan, Isoptin),
• diltiazem,
• amlodipine (Norvasc),
• danazol (Danocrine),
• ranolazine (Ranexa),
• niacin (Niacor, Niaspan, Slo-Niacin),
• gemfibrozil (Lopid) and
• fenofibrate (Tricor).

This isn't a full list of drugs that interact with simvastatin and rosuvastatin, so make sure you tell your doctor about all the medications you're taking if they prescribe you either of these drugs.

Neither Crestor nor Simvastatin should be taken during pregnancy or breastfeeding. Cholesterol is absolutely vital for the developing fetus and growing infant, so cholesterol reducing medications like Crestor and Zocor. Furthermore, statins are passed on in breastmilk, so either don't take them while nursing or feed your baby formula.