Drug interactions can pose medical concerns for patients

The term drug interaction is used to describe a situation in which the way a medication would normally act in the body is altered because of another substance. Interactions can occur with food or other drugs, and can adversely affect medical conditions. Frequency Severe drug interactions are not common, but there are risks. A few years ago, Seldane, a prescription medication for allergies, was pulled from the market, in part because interaction with other drugs sometimes resulted in heart problems and patient deaths. Most interactions are much less dangerous and may be so subtle that patients aren’t even aware that they’re occurring. Food in the stomach, for example, may affect the absorption of a drug into the bloodstream. But it may not cause a person to feel any different. Drug interactions that a patient would actually notice are not all that common. Occasionally, drugs interact with food in adverse ways. Certain cholesterol medications have been shown to interact with grapefruit juice in ways that cause problems. Affected patients may experience muscle aches, or in more severe cases, could result in a breakdown of muscle tissue. Sometimes it’s not the interaction of two drugs that’s problematic, but rather, the condition treated by one drug that is adversely affected by the other medication. For example, Sudafed, which is used to treat nasal congestion, can increase your blood pressure. So if you’re taking blood pressure medication, Sudafed could counteract the effects of the blood-pressure drug. People should be aware that even Sudafed and other over-the-counter medications (ones that you can buy without a prescription) could interact with drugs that are taken by prescription. Prevention There are several things that people can do to lessen the risk of drug-drug interactions. First, make sure your physician is aware of all the medications that you’re taking. This list should include any prescription and non-prescription drugs, in addition to any herbal medications you’re taking. Not everyone considers herbals to be drugs, but studies have shown that they occasionally interact with prescription medications in adverse ways. Secondly, you should use one pharmacy, so all your medication records will be kept in one place. Pharmacists always review each patient’s profile personally, and pharmacy computer systems alert them to potential interactions. Each pharmacist then uses his or her professional judgment to determine what interactions a patient might encounter. If potential red  flags pop up, your pharmacist will consult with your doctor. Solving the problem may be as simple as changing the time of day you take the medication (for example, between meals, so they don’t interact with food) or it may require an alternative prescription medication. See a pharmacist If anything seems abnormal, ask your pharmacist or physician about it. The symptoms of drug interactions can run the gamut from general malaise to heart palpitations. There’s no particular rule about what you can expect with a drug interaction. But you can ask your pharmacist about the medications you are taking: If something were to occur, what are the potential signs? When is it likely to happen? The symptoms of drug interactions can be predicted in some cases. The main thing to remember is that good communications with all your health professionals is key. Patients shouldn’t be expected to identify these things themselves, but they should always feel comfortable asking questions. Todd D. Sorensen is a professor with the College of Pharmacy at the U of M. This column is an educational service and advice presented should not take the place of an examination by a health-care professional. To ask a health-care expert at the U a question or for more health-related information, go to www.healthtalkandyou.com.