Lipitor and similar cholesterol medications increase the risk of liver damage.  You should check with your doctor, who may ask for you to have a blood test to check your liver functioning before you start taking the drug again, approximately 12 weeks after you begin therapy with this medication, or if you're dosage is increased, and periodically for some time thereafter.  If the blood test reveals a problem with your liver, you may have to stop taking this cholesterol medication. 

Also, Lipitor and similar cholesterol medications have been known to damage muscle tissue, so you should always notify your doctor immediately if you notice any unexplained muscle tenderness, weakness or pain, and especially if you also have a sick feeling or a fever.  Your doctor may then want to do a blood test to check for signs of muscle damage. 

If you're going to have some type of major surgery, your physician may ask you to stop taking this medication several days before the operation. 

Lipitor should never be taken while pregnant as developing babies need plenty of cholesterol in their development.  In fact, in most cases, physicians will not even prescribe Lipitor or similar cholesterol medications if you are even anticipating becoming pregnant some time in the near future.  If you do conceive while taking Lipitor, you should notify your doctor immediately.  Lipitor is also known to make its way into the breast milk so you should never take this drug while breast-feeding your baby.