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Are You Mixing the Wrong Drugs?

Debra Gordon

Last updated: October 20, 2016 7:34 pm

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Seventy percent of us take at least one medication every day, according to a study published in the journal Mayo Clinic Proceedings, more than half take at least two, and 20 percent – a whopping one in five – take five or more medications a day. Antibiotics, antidepressants, and narcotic pain relievers are the most common drugs.

Understanding Prescription Drug Risks

All drugs have risks. And one of the most dangerous is an interaction with other medications. Even though pharmacies use software that automatically flags drugs for interactions, it doesn’t tell the pharmacist which interactions are “clinically significant,” ie, truly dangerous.

And don’t rely on your doctor to remember all the various drug interactions. As an article in American Family Physician, the journal of the American Academy of Family Physicians, noted: “It is no longer practical for physicians to rely on memory alone to avoid potential drug interactions.”

To that end, here are the most common, clinically significant drug interactions. If you are taking such drugs, or your doctor prescribes one that interacts with another you’re taking, ask about alternatives. Just remember: Never stop taking a medication without first checking with your doctor, and always tell your doctor everything you’re taking, including over-the-counter medications, vitamins, minerals, and herbal and nutritional supplements.

Dangerous Medication Interactions

If you’re taking . . . Then try to avoid . . . * Because they may . . .
Coumadin (warfarin) These antibiotics: ciprofloxacin, metronidazole and trimethoprim, sulfamethoxazole, azithromycin, clarithromycin, erythromycin, telithromycin Make warfarin less effective
Acetaminophen (Tylenol). More than 2 grams a day for a week
Aspirin  Increase your risk of bleeding
Non-steroidal anti-inflammatories (Motrin, Aleve)
Fluoroquinolone antibiotics such as Avelox (moxifloxacin), Cipro (ciprofloxacin), or Levaquin (levofloxacin) Calcium, magnesium/aluminium (Maalox, Mylanta, etc), aluminum (Alu-Cap, AlternaGel, etc), iron, magnesium Reduce absorption of the antibiotic 60 to 70 percent
Tegretol (carbamazepine), Dilantin (phenobarbital and phenytoin) The antibiotics azithromycin, clarithromycin, erythromycin, and telithromycin, Tagamet (cimetidine), and Diflucan (fluconazole) Inhibit an enzyme called cytochrome P450, which helps your liver metabolize these drugs, resulting in a dangerous build up of the medications
Rifadin (rifampin) Reduce absorption of the drug resulting in breakthrough seizures
Lithium  Diuretics and non-steroidal anti-inflammatories (Motrin, Aleve)  Affect how the kidney works, which could increase blood levels of lithium
Oral contraceptives  Rifampin (and, possibly, other antibiotics); Rezulin (roglitazone)  Lead to breakthrough bleeding and increased risk of pregnancy
Propulsid (cisapride) The antibiotics azithromycin, clarithromycin, erythromycin, and telithromycin, Tagamet (cimetidine), and Diflucan (fluconazole)  Result in potentially fatal effects
Viagra (sildenafil) Any form of nitrates  Lead to extremely low blood pressure
Erythromycin, Tagamet (cimetidine), Nizoral (ketoconazole), and (Sporanox) itraconazole  Increase the amount of drug in the bloodstream
Lipitor (atorvastatin), Baycol (cerivastatin), Lescol (fluvastatin), Mevacor (lovastatin), Pravachol (pravastatin), Zocor (simvastatin)  Erythromycin, Sporanox (itraconazole) niacin, Lopid (gemfibrozil) Lead to kidney failure and muscle damage, among other serious effects

*Other drugs may also cause interactions; these are the most common