I recently had a phone call from a former patient whose new medical insurance did not cover my services or laboratory tests at Johns Hopkins. For several years I had successfully treated his high cholesterol with the statin simvastatin (Zocor). He was concerned because his internist stopped his Zocor when a blood test showed that one of his liver enzymes was slightly high at 57 IU/L in a lab where the upper limit of normal is 40 IU/L.

I told him that such a small elevation in a liver enzyme is not a reason to discontinue taking a statin. His doctor seems unaware of the recommendation that a statin should be stopped if a liver enzyme increases to three times the upper limit of normal, about 120 IU/L in this laboratory. His doctor is not alone in his undue concern about liver damage from statins; a number of people have made appointments to see me under similar circumstances.

Because statins can raise liver enzymes, blood tests of liver function must be obtained periodically when taking these drugs. But on the uncommon occasions when statins do raise liver enzymes to high levels, they promptly return to normal when the drug is stopped. I am not aware of any instance of permanent liver damage caused by a statin.

I could not help him figure out how to tell his doctor about my advice, however.