Avoiding Drug InteractionsIn my earlier newsletter on conditions that mimic Alzheimer's disease, I suggested making a list of all your medications and nutritional supplements and keeping it in your purse or wallet. If you haven't done that yet, please do it now so the list is at hand in case of emergencies or visits to the doctor or pharmacy. Many people see more than one physician and use more than one pharmacy, so it's important to be able to share this information with each one. While it's impossible to detail every potential drug interaction, I can tell you that problems occur in four general areas:
- Mixing drugs with alcohol
- Mixing drugs with food
- Mixing drugs with nutritional supplements
- Mixing drugs with other drugs
Drugs and AlcoholMany people are aware that mixing alcohol with sedatives is a recipe for disaster. But did you know that combining alcohol with certain antibiotics is also a terrible idea? Bactrim, for example, is a popular antibiotic for treating ear infections, pneumonia, urinary tract infections, and similar problems. Drinking alcohol while taking Bactrim can cause vomiting, headache, shortness of breath, rapid heartbeat, profound fatigue, serious bone pain, and skin rashes. While taking Bactrim, adding even a cough remedy or mouthwash containing a bit of alcohol can cause this type of reaction. So if you like to enjoy a cocktail or glass of wine at the end of the day and if you have been prescribed an antibiotic or other medication, be sure to ask your physician about the possibility of an alcohol-drug interaction.
- Alcohol can boost a drug's availability in the body, adding to the likelihood of negative complications.
- Alcohol can essentially cancel out a drug's effect.
- Certain drugs may enhance the effects of alcohol. In this case, just a drink or two can have the same result as downing several times that amount.
- Alcohol can combine with some drugs to create toxins that may harm the liver, kidneys, or other organs.
- The effects of alcohol may interfere with drugs even when an individual is not drinking. For example, if a heavy drinker stops ingesting alcohol, it could take weeks for some medications to work.
- Certain antibiotics, including Flagyl (metronidazole) and Furoxone (furazolidone)
- Anticoagulants, such as Coumadin (warfarin)
- Antidepressants, especially tricyclic antidepressants like Elavil (amitriptyline)
- Antihistamines, such as Benadryl (diphenhydramine)
- Heart and high blood pressure medications, including nitroglycerin and Inderal (propranolol)
- Pain relievers, both prescription and nonprescription, including aspirin
- Sleep aids and tranquilizers, such as Ativan (lorazepam) and Dalmane (flurazepam)
Drugs and FoodThere are two primary concerns when it comes to combining drugs and food. One is that a number of medications must be taken with or without food to be effective. Generally, this is clearly marked on the bottle. Some drugs, for example, can cause nausea or an upset stomach if taken on an empty stomach, so you'll be instructed to take it with food. In other cases, food may interfere with absorption of a pill, so you'll be instructed to take it on an empty stomach. Please follow these instructions carefully. The second primary concern is that certain foods may affect how the body processes the medication. Several types of citrus are good examples -- most notably, grapefruit and its juice, along with a grapefruit relative known as pomelo, and Seville oranges. These fruits contain compounds that affect the way the body metabolizes particular drugs, including some immunosuppressants that are often given to transplant patients. Combining medications with these citrus fruits could cause the drug to remain in the body. As you continue taking your regular dose, the amount of the drug accumulates. Eventually, drug levels could reach the point of causing an inadvertent overdose. If you are taking medication that interacts with grapefruit or other citrus fruit, you'll need to stop eating or drinking the citrus completely. Taking the drug at a different time than the food or drink is not enough to prevent this potentially serious side effect.
- Zoloft (antidepressant also sold as sertraline)
- Allegra (antihistamine also known as fexofenadine)
- Procardia, Nimotop, Sular (calcium channel blockers also sold as nifedipine, nimodipine and nisoldipine)
- Statin drugs like Lipitor, Zocor, Mevacor (also known as atorvastatin, simvastatin, and lovastatin, respectively)
- Warfarin (Coumadin) and foods high in vitamin K: Foods high in vitamin K (spinach, broccoli, kale, and other leafy greens) may interfere with the effectiveness of the blood thinner warfarin (also known as Coumadin). If you're a regular salad eater, it's fine to continue. But a sudden increase in leafy greens could cancel out the drug's benefits.
- Antibiotics and dairy products or calcium supplements: Dairy products or calcium supplements may inhibit the absorption of antibiotics. This is especially likely with the group of antibiotics known as quinolones (sold as Cipro, Avelox, Factive, Tequin, Floxin, and Levaquin). To avoid this problem, take the antibiotics at least two hours prior to taking supplements or four to six hours after taking them.
Drugs and Nutritional SupplementsVitamins, minerals, and herbal supplements are increasingly popular as more and more people discover the downsides of drugs. For some individuals, that means mixing nutritional supplements with various medications. Again, it's best to check first with a pharmacist or a well-informed physician who has some familiarity with nutritional supplements.
- Blood pressure medications and potassium supplements: Taking potassium supplements with any of several different blood pressure medications (including ACE inhibitors, diuretics, or beta-blockers) could lead to dangerously high potassium levels, a condition known as hyperkalemia. Symptoms include nausea, weakness, heart arrhythmia, and fatigue. If you're taking blood pressure medications, talk with your health-care provider before adding potassium supplements.
- Blood thinners and garlic, ginger, curcumin, or ginkgo biloba: Combining these supplements with blood thinners such as Plavix or warfarin (brand name Coumadin) may cause blood to become too thin.
- Diabetes medication chlorpropamide and garlic supplements: Mixing garlic supplements with chlorpropamide could cause blood sugar levels to drop.
- Corticosteroids and licorice supplements: Taking licorice supplements, a natural cough or cold remedy, with corticosteriods may increase blood pressure and may also amplify the effects of the corticosteroids.
Drugs and Other DrugsHere again, there is simply no way to cover all possible drug-drug interactions. There are literally thousands of different prescription and over-the-counter medications plus thousands of herbal and vitamin formulations. That's why it's so important to carry a list of all the medications and supplements you are taking whenever you go to the doctor or pharmacy. Yes, I am repeating myself, but only because this information may save a life or avoid a medical catastrophe. This is a partial list of some of the drugs that commonly cause unwanted interactions:
- Benzodiazepines (antidepressants)
- Diuretics, beta-blockers, and calcium channel blockers used to treat high blood pressure and heart disease
- Pseudoephedrine and ephedrine, common ingredients in cough and cold medicines
- Blood thinners such as Coumadin (warfarin)
- Steroids like prednisone
- Nonsteroidal anti-inflammatory drugs (NSAIDs), including ibuprofen
- Digestive aids with H2 blockers, such as Tagamet (cimetidine)