Hello Norma,

Both medications are used to treat "high cholesterol," but they are used to treat different parts of the cholesterol panel and they have different side effect to watch out for.

Crestor is the brand name of rosuvastatin, which belongs to the statin class of drugs.  The drugs in that class inhibit an enzyme that assembles the cholesterol molecule in the body.  It is a good drug because if mainly lowers the LDL-cholesterol (the "bad" cholesterol) part of the lipid panel. They can cause muscle aches and can elevate the liver enzymes.  Because of this, your doctor will monitor your liver functions tests while taking the drug.

Niaspam is a potent form of the vitamin niacin.  It is mainly prescribed to lower the triglyceride portion of your cholesterol (or lipid) profile; it also raises HDL cholesterol, or the "good" cholesterol.  It can cause flushing of the face and body which can be quite annoying, though not harmful.

Hope this helps.

To your health,

Neil MD