Some meds could cause liver damage.(Knight Ridder Newspapers)

Q. You recently wrote about liver damage caused by taking too much acetaminophen. I take phenytoin (Dilantin) and primidone (Mysoline) for seizure control. My ALT level (test of liver function) was high (47) on my last doctor visit, which he said is a minimal elevation. Should I be worried and does either medicine contain acetaminophen?

Q. I am taking gemfibrozil (Lopid) to lower my triglycerides. I read that this drug can cause liver damage and that I need to be checked for this every four months. Should I be concerned?

A. The liver breaks down most drugs for elimination by the body, so it's not surprising that some drugs can be hard on this organ.

To answer the first question: Neither of your medications contains acetaminophen, but phenytoin itself has occasionally caused liver damage.

That's probably why your doctor keeps tabs on your liver function with the ALT test. High levels of this enzyme can indicate a liver disorder. However, as your doctor said, your tested level does not seem to be seriously high (normal levels are below 40).

The second question: When you take a drug that is potentially harmful to the liver, such as gemfibrozil, make sure your physician checks your liver function at appropriate intervals to keep you safe.

To test liver function, blood levels of certain substances are measured. These include liver enzymes such as ALT as well as bilirubin.