Lipitor is the largest-selling drug in a class known as statins, and is used by millions of patients worldwide to help lower their LDL cholesterol. Lipitor works by inhibiting a key enzyme, HMG-CoA reductase, which is needed to manufacture cholesterol in the liver.
Numerous clinical studies studies have demonstrated the benefit of Lipitor in reducing the risk of heart attack and stroke in patients with cardiovascular disease. While the accumulated safety record for Lipitor is excellent, as with all drugs there are associated side effects in susceptible patients that may become apparent only after long-term usage.
Lipitor elevates liver enzymes in a small percentage of patients, usually within the first few months of therapy. For this reason, most patients taking Lipitor should start with a lower dose as recommended by a physician. Elevated liver enzymes are usually not associated with any symptoms, and are reversible upon discontinuation of the drug.
However, this side effect has raised concerns about potential long-term effects of Lipitor on the liver since occasional, but rare, reports of liver failure have appeared. Although no definite link has been established between Lipitor use and liver failure, Lipitor should not be used in patients with active or chronic liver disease.
Mild muscle pain or myopathy is a common side effect of many statin drugs, including Lipitor. This problem is more common in Lipitor patients who are taking certain other drugs such as cyclosporine or fibric acid derivatives.
Continuous and severe muscle aches that develop over time in patients on Lipitor could be a sign of a disease called rhabdomyolysis. If unchecked, rhabdomyolysis can lead to kidney failure and even death. This potential complication of Lipitor is monitored by checking creatine phosphokinase (CPK) enzyme levels in the blood of patients.
Fortunately, rhabdomyolysis is extremely rare in patients taking Lipitor. In 2001, another statin drug called Baycol was recalled from the market after being implicated in more than 60 deaths due to rhabdomyolysis. Since then, drug manufacturers have added a warning to statin advertising about the risk of unexplained muscle pain and weakness.
Memory loss was not detected in the thousands of patients who took Lipitor prior to its approval and commercialization, and no warning for memory loss exists on the product label.
However, over its years of use in millions of patients, there have been a number of patient complaints suggesting that Lipitor affects memory. No direct studies have ever linked Lipitor to memory loss. However, it may take thousands of patients and several years of drug use before a rare drug side effect appears.
Perhaps this possible side effect of Lipitor may be related to the drug's inhibition of steroid molecules that are involved in memory function. Ironically, there was some preliminary evidence that Lipitor might prevent Alzheimer’s disease by enhancing memory function. Unfortunately, this beneficial effect was not confirmed in larger studies.
As with all drugs, Lipitor has side effects. However, serious side effects, such as liver damage, rhabdomyolysis and perhaps memory loss, are very rare, even after millions of patients have taken the drug for several years. For many patients with cardiovascular disease, the benefits of Lipitor far outweigh its risks.