Ask Dr. Zipes
Drug Safety Concern
By Douglas Zipes, M.D.
From the July/August 2005 Issue
Reader: I am 52 years old and have episodes of paroxysmal atrial fibrillation. I am taking amiodarone, initially 1,600 mg daily and now 200 mg, along with diltiazem and aspirin. Is amiodarone a safe drug to use long term? Dr. Zipes: Amiodarone is probably the most effective drug available to treat paroxysmal atrial fibrillation. Diltiazem does not do much to prevent episodes of atrial fibrillation but helps to control your heart rate when they do occur. Other drugs are available to suppress the paroxysms and can be tried. Sometimes they are effective and may cause fewer side effects than amiodarone. There is also an invasive procedure, called catheter ablation, that can cure some patients by eliminating the atrial fibrillation. Amiodarone can adversely affect many organs, including (most commonly) skin, lung, liver, thyroid, eyes, and nerves. However, monitoring these organs can catch early changes, which generally are reversible if the drug is then stopped. In addition, since most side effects are dose related, the fact that you are taking 200 mg a day should reduce your chance of having an adverse response. I have cared for many patients taking amiodarone for years without problems, but I monitor for adverse effects carefully.Stopping Tachycardia Reader: I have had two catheter ablation attempts at excellent teaching hospitals, but I go into heart block each time they tried to ablate. I am very athletic and am now taking Sotalol. It seems to be working better than my other medications, but I would like to know if there are any other procedures available. Dr. Zipes: I assume from your question that you have episodes of rapid heartbeats, so-called "tachycardia," that are related to an "extra" pathway in your heart, and that your doctors tried to eliminate it by the procedure called catheter ablation. As you know, this involves threading a catheter (skinny wire) into your heart and positioning the tip near this extra pathway to burn it and stop the tachycardias. Most likely, in your case, the extra pathway is very close to your heart's normal conducting system, and each time the doctors tried to burn the abnormal pathway, they temporarily blocked your normal pathway also. You don't say how long ago these procedures were tried, but there have been many improvements in catheter ablation over the past few years. I suggest you talk with the doctors who last tried the procedure and ask if they think it might be worthwhile to try again. If you like, you can contact me directly for suggestions of other doctors who might help.Grapefruit and Statins Reader: I have taken Lipitor for a number of years and just learned that grapefruit juice is contraindicated when taking it. I have also eaten grapefruit while taking Lipitor with no adverse effects. Have I just been lucky? Dr. Zipes: Grapefruit and its juice contain a compound that partially blocks one of the enzymes in the liver that metabolizes (breaks down) many drugs, including some statins such as atorvastatin (Lipitor). Slowing or blocking the metabolism of a drug can lead to increased blood levels of the drug, and in some instances, depending on the drug, can be quite dangerous. You don't state what dose of Lipitor you are taking, but we are now prescribing doses as high as 80 mg a day. So, unless you are taking that high dose, I don't think you need to worry. In fact, the grapefruit may be increasing the effectiveness of the Lipitor! However, it is always a good idea to check your lipids and blood chemistries periodically while taking a statin, and if you have not done that in a while, it might be a good idea to do it now.Seek Maximal Care Reader: My doctors determined that my heart was damaged by radiation, which I received for seven weeks in 2001 to treat lung cancer. My doctor says that I now have atrial fibrillation, a leaky fight-sided heart valve, elevated pressures in my lung arteries, and chronic lung disease. I use oxygen 24 hours a day and am concerned about what possibly could happen next. Dr. Zipes: It sounds like you are suffering from more than just the effects of radiation on your heart. I think much of what you have also resulted from damage produced by smoking over many years (you don't say how long). Medications can help your problems to some degree (you don't say what drugs you are taking) and help make you feel better. However, it is likely you will require the oxygen for the rest of your life. My best advice is to be sure you are being cared for by someone who is knowledgeable about your heart (cardiologist) and lungs (pulmonologist) so that you receive maximal care to treat both of your problems.
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