INDIVIDUALS who have heart disease or who are at risk for it - and probably take two or more prescription drugs - need to know about foods, beverages, vitamins, dietary supplements, over-the-counter drugs, or other prescription medications that could interact with their medications, says the June 2013 issue of the Harvard Medical School’s Harvard Heart Letter.

An interaction may cause the drug to become more powerful or less effective - if either happens to you, your heart disease could progress, or you might be at increased risk for a heart attack or fatal arrhythmia, warns the heart letter.

While interactions don’t always occur, no one knows who will experience a problem and who will not - Dr. Richard Lee, a cardiologist and co-editor-in-chief of the Harvard Heart Letter, says, “To be on the safe side, we counsel everyone to avoid products that may interact with their medications.”

The heart letter offers a list of products known to interact with heart medications, which may include:

• An ACE inhibitor, such as isinopril (Prinivil, Zestril), enalapril (Vasotec), ramipril (Altace) = Avoid: Because ACE inhibitors cause increased potassium levels, be sure your doctor checks those levels periodically if you take over-the-counter salt substitutes (which contain potassium) or if you eat many high- potassium foods (bananas, oranges, green leafy vegetables); Why: High blood potassium levels can cause dangerous heart rhythms

• The anti-arrhythmic drug amiodarone (Cordarone, Pacerone) = Avoid: The statin drug atorvastatin (Lipitor), rosuvastatin (Crestor) and simvastatin (Zocor); Why: These statins increase risk of a severe muscle injury that can lead to kidney failure or death     

• Aspirin: Avoid: Fish oil, Vitamin E, ginkgo, garlic, ginger, feverfew, ginseng, policosanol and tamarind; Why: These supplements increase the risk of bleeding

• A beta blocker, such as atenolol (Tenormin), metoprolol (Toprol), or propranolol (Inderal); 1) Avoid: Black licorice, alcohol (a problem with propranolol only): Why: May lower blood pressure excessively; 2)Avoid: Hawthorn; Why: The interaction may increase blood pressure and heart rate

• A calcium-channel blocker, such as, amlodipine (Norvasc) or felodipine (Plendil); 1) Avoid: Grapefruit and its juice; Why: Makes the drug more powerful; 2) Avoid: Hawthorn; Why: May lower blood pressure; 3) Avoid: St. John’s wort; Why: May make the calcium-channel blocker less effective  

• Clopidogrel (Plavix); 1) Avoid: Fish oil, Vitamin E, ginkgo, garlic, ginger, feverfew, ginseng, policosanol and tamarind; Why: These supplements increase the risk of bleeding; 2) Avoid: St. John’s wort; Why: This supplement makes clopidogrel less effective

• Digoxin (lanoxin); 1) Avoid: High-fiber foods, such as bran; Why: May weaken the effect of digoxin; 2) Avoid: St. John’s wort, senna; Why: These supplements  make digoxin less effective; 3) Avoid: Black licorice and other foods containing glycyrrhizin; Why: May cause irregular heartbeat or heart attack; 4) Avoid: Hawthorn; Why: May increase blood pressure and heart rate

• Spironolactone (Aldactone); Avoid: High-potassium foods, such as bananas, oranges, green leafy vegetables, salt substitutes, potassium supplements, diuretics; Why: May raise blood potassium levels and cause dangerous heart rhythms

• A nitrate, such as nitroglycerin (Nitrostat) or isosorbide mononitrate (Imdur); 1) Avoid: Alcohol; Why: May cause dangerously low blood pressure; Avoid: Hawthorn; Why: May lower blood pressure

• A statin, such as atorvastatin (Lipitor) or simvastatin (Zocor); 1) Avoid: Grapefruit and grapefruit juice, limes, Seville oranges, pomelos; Why: May make the statin more potent, increasing the risk of side effects; 2) Avoid: St. John’s wort; Why: May render the statin less effective

• Warfarin (Coumadin, Jantoven); 1) Avoid: Varying from one day to the next your intake of foods high in Vitamin K (broccoli, cabbage, collard greens, spinach, kale, turnip greens, beet greens, Brussels sprouts, canola oil, soybean oil - It’s important to get some vitamin K each day and ideally the same amount; Why: Vitamin K makes warfarin less effective; 2) Avoid: Herbal teas, green tea and many herbal medicines, including St. John’s wort, coenzyme Q10, feverfew, evening primrose oil, dong quai, danshen; Why: Can make warfarin more or less effective; 3) Avoid: Cranberries, cranberry juice; Why: Increases the risk of bleeding; 4) Avoid: Ginseng; Why: Decreases the effectiveness of warfarin; 5) Avoid: Garlic, ginkgo, Vitamin E; Why: Increases the risk of bleeding; 6) Avoid: Ginger supplements, glucosamine; Why: Reduces warfarin’s effectiveness; 7) Avoid: More than three alcoholic drinks per day; Why: Enhances blood thinning; 8) Avoid: Certain antibiotics. If you need to take an antibiotic, make sure the clinician prescribing it knows you take warfarin so he or she can choose an antibiotic that doesn’t react with warfarin or, if it will, your doctor can temporarily change your warfarin dose; Why: Increases risk of internal bleeding

These medication safety tips are offered to help you avoid potentially dangerous interactions:

• Using the list provided above, locate the medications you take, check the products you need to avoid and save the list in a safe place.

• Tell your doctor about any vitamins or dietary supplements you are taking.

• Whenever you are given a new prescription for any reason, ask your doctor if there are any foods, beverages, vitamins, dietary supplements, or other medications that may react with it - write them down and post the list on your refrigerator door.

• Obtain all your prescriptions from the same pharmacy.

• Read the information that comes with prescription drugs and over-the-counter medications, as well as the “drug facts” printed on bottle labels.

To conclude, Dr. Lee says, “When it comes to your drugs, there’s no such thing as a silly question. If you are even remotely concerned about a medication, ask your doctor or pharmacist.”