What you should know about mixing your medications

October 30, 2010|By MARIE GILBERT |
  • Mixing medications such as taking a cough medicine with another medication can be dangerous. According to the Journal of the American Medical Association, older people are more vulnerable to side effects and drug-to-drug interactions.
Photo illustration by Joe Crocetta/Staff Photographer

Every morning, millions of people start their day by following their doctor's orders.

They open a bottle of prescription medicine and pop a pill.

At the same time, they might take a dose of cold medicine to tackle that stuffy nose.

Seems innocent enough.

But the combination of certain prescription drugs and over-the-counter remedies can sometimes have serious consequences.

For instance, according to the Food and Drug Administration, taking pain reducers and prescription blood thinners can cause gastrointestinal bleeding.

Decongestants and diabetes drugs? Together, they can create hypertension and poor glucose control.

It may be a hard pill to swallow, but consumers are unknowingly putting themselves in harm's way by mixing drugs and off-the-shelf products, said Sheryll Smith, a retired geriatric nurse.

Even certain dietary and herbal supplements can pose a danger, she said.

That's why, over her many years of nursing, she has always stressed the importance of talking to your doctor or pharmacist before adding any over-the-counter products to your system.


"By talking to a medical professional, you can avoid adverse reactions," Smith said. "But sometimes it's difficult to make people realize that nonprescription products contain powerful ingredients."

This is a point stressed by the American Pharmacists Association, which notes that many of the products available on your store shelf today were prescription medications just a few years ago. So don't underestimate their strength.

Mixing medicine is a particular problem among senior citizens, Smith said - many of whom live alone and don't have someone to check on their use of medicines.

According to a study by the Journal of the American Medical Association, almost 70 percent of older adults who take prescription medications also use nonprescription drugs, dietary supplements or both. One in 25 is at risk of suffering a bad reaction to a poor combination of drugs.

The study, published in the Journal of the American Medical Association, analyzed a nationally representative sample of more than 3,000 adults, ages 57 to 85.

Ninety-one percent in this age group use at least one medication, often for heart disease and related problems. More than half use at least five remedies, including prescriptions, over-the-counter medicines or supplements.

Among older men, the numbers are particularly unsettling - 10 percent are taking potentially harmful combinations.

Results aren't always disastrous. But the study noted older people are more vulnerable to side effects and drug-to-drug interactions.

That's why Smith believes the most important advice is to talk with a health professional about any side effects of any medicine - prescribed or store-bought.

Smith said consumers should also be aware of dietary and herb supplements.

The FDA reports that it does regulate herb or dietary supplements. But according to, manufacturers don't have to seek the FDA's approval before putting them on the market.

Multivitamins are a great source for most of the vitamins and minerals we need, Smith said. But too much calcium could lead to problems, including toxicity, gastrointestinal disorders, renal failure and psychosis. Too much iron can lead to hypertension, respiratory failure and cardiac disturbances.

What about over-the-counter medications taken specifically for colds?

"Taken as directed, they are mostly OK with some exceptions," she said. For example, "they have the potential to have an adverse reaction when combined with hypertension medications."

Smith said it's important for the elderly to maintain a healthy, informative relationship with their doctors, "who constantly need to be aware of every medication being taken, whether it's by prescription or over-the-counter."

And it is possible, says the American Pharmacists Association, that store-bought and prescription medications may still be combined - but it should be done under a doctor's watchful eye.

Pharmacies typically use databases that flag potential drug interactions, the association notes. But using them properly requires patients to disclose all the medications they're taking and any drug allergies they have.

Nothing replaces conversation, the group stresses.

Online "drug interaction checkers" also are available on websites of such major medical centers, retailers and pharmacies as Caremark, the University of Maryland Medical Center,, Eckerd and Discovery Health.

But the absence of a warning doesn't mean a drug combination is generally safe - or, more important, safe for you in particular. Many factors, including a patient's health and medical history, can affect health, the pharmacists' organization stresses. The best advice, is always check with your doctor for specific advice.

Drugs are treated too casually in society, Smith said. "And the reality is, they all have a risk."

Safety first

Tips to avoid complications from mixing prescription and over-the-counter drugs:

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