Lipitor
Lipitor Side Effects: The generic name for Lipitor is atorvastatin. With the patent expiration of Lipitor in Nov. 2011 atorvastatin use has become much more prevalent, and this is expected to continue as less expensive generic atorvastatin products come to the U.S. market by mid-2012. Liptor is available in 10, 20, 40 and 80 mg tablets. It is currently an expensive branded drug, and so doctors often advise patients to break a larger dose in half, i.e. a 40 mg tablet prescribed as ½ orally each day, to provide a 20 mg dosage. Lipitor is used to lower LDL cholesterol in patients for whom lowering LDL cholesterol can reduce the risk of cardiovascular diseases like heart attack, stroke, and peripheral vascular disease. Lipitor is one of the most potent of the statin medications and is highly effective at lowering LDL cholesterol. Lipitor can also be used to treat hypercholesterolemia, certain mixed hyperlipidemias, and in children for certain heterozygous familial hyperlipidemias.
Common Lipitor Side Effects: The most common Lipitor side effect is myalgia, which tends to present itself as muscle pain and weakness, varying from mild to severe. In its most severe form this can be what is called rhabdomyolysis, a condition where muscle cells are broken down releasing large amounts of degraded proteins into the blood stream. Protein degradation can lead to acute renal injury and failure. This severe form is very uncommon, even rare, but mild to moderate myalgia is common. Other common Lipitor side effects include arthritis/arthralgias, diarrhea, headache, rashes, elevation of liver transaminases, elevation of creatine kinase (a muscle enzyme), various gastrointestinal symptoms including flatulence, dyspepsia, and abdominal pain, and various infection symptoms.
Life Threatening Lipitor Side Effects: Rhabdomyolysis, the acute breakdown of large amounts of muscle tissue with severe muscle pain and the release of huge amounts of muscle protein into the blood stream is rare but well documented as a serious Lipitor side effect. This can lead to acute renal failure in serious cases, and it is very important to seek immediate medical attention for treatment because early intervention can sometimes prevent the need for dialysis. Hepatotoxicity is another serious Lipitor side effect. It can be asymptomatic or can lead to right upper quadrant abdominal pain and jaundice in more severe cases. Allergic reactions including Stevens-Johnson Syndrome, toxic epidermal necrolysis, photosensitivity, vasculitis, polymyalgia rheumatica, angioedema, anaphylaxis, and others can be serious too. Pancreatitis is a rare but serious Lipitor side effect. Lupus erythematosis is also a rare, but recorded, as a Lipitor side effect. Even considering these side effects, Lipitor is well tolerated in the vast majority of patients, and except for mild to moderate myalgias and weakness as noted in the Common Lipitor Side Effects section above, most patients tolerate Lipitor quite well.
Unusual Lipitor side effects: Pancreatitis and Rhabdomyolysis are probably the most unusual Lipitor side effects of note.
Contraindications, cautions and drug interactions: Lipitor is contraindicated for use with the azole antifungal as well as the HIV protease inhibitors and telaprevir. Of course Lipitor is contraindicated for use with patients with history of hypersensitivity to Lipitor itself or other drugs in its class. Special caution needs to be taken in patients with active hepatic disease or unexplained significant elevation of liver function tests. Due to the potential of Lipitor to cause muscle inflammation Lipitor should be avoided in patients with active myopathy or who have significantly elevated baseline CK levels. Recent studies suggest that like the other statins Lipitor should not be initiated as therapy in the immediate preoperative timeframe, although if patients have been on Lipitor for period of time it is probably best to continue use of Lipitor throughout the perioperative period. Use of Lipitor during significant electrolyte imbalances are patients with severe dehydration, uncontrolled surgery or unmanaged hypothyroidism requires caution.
Lipitor is extensively metabolized by the liver using the common cytochrome P-450 3A4 pathway, and so has an extensive list of potential drug interactions. Some of the most important are listed here, but see the manufacturer’s prescribing information for a more complete discussion. Some of these include amiodarone, cyclosporine, diltiazem, erythromycin’s, isoniazid, gemfibrozil, any of the other Staton medications, red yeast rice (a statin alternative herbal medication), rifampin, and for verapamil. Modification of Lipitor therapy may be required in another extensive list medication which again is only briefly discussed here. Interestingly this includes grapefruit. Other medications requiring monitoring or modification of treatment include digoxin, fenofibrate, the phenytoin, the barbiturates, carbamazepine, tamoxifen, oral contraceptives, fluoxetine, and a large number of herbal medications including St. John’s wort, and milk thistle.
Pregnancy and Lactation Class: Pregnancy Category X – this means that there are clearly proven adverse effects of Lipitor in pregnancy, and that the risks clearly outweigh the benefits. Lipitor is considered possibly unsafe to use during lactation.
Special Considerations: Generally Lipitor, like other statin medications, should be avoided in women for whom pregnancy is a significant possibility. It is one of the more potent statins in terms of its LDL lowering capability, with approximately 55 percent mean LDL reduction at peak dosing. Like with other statins the chances of myalgia increases with increasing dose. Lipitor is one of the statins with the most data for efficacy in secondary cardiovascular disease prevention. Overall the whole statin class has been a breakthrough in secondary and primary cardiovascular disease prevention, and the Lipitor side effects are uncommon enough that it has become very widely used.
The potential interaction between grapefruit and Lipitor is potentially significant, especially at higher Lipitor dosage. Lipitor uses the CYP 450 pathway for metabolism, and is a 3A4 substrate. This means that some of the Lipitor ingested is metabolized in the small intestine by the intestinal 3A4 brush border enzymes. Grapefruit and grapefruit juice contains chemicals that lead to an irreversible competitive blockade of the 3A4 intestinal enzyme sites and allows a much higher rate of absorption of drugs broken down by this 3A4 enzyme including Lipitor. Some authorities raise the concern that the potential dose related Lipitor side effects like myopathy may be more common when Lipitor users also ingest grapefruit.
