Photo courtesy FDA/MedWatch
Drug interactions occur when another medication, supplement or food interacts or interferes with a drug, causing an adverse drug reaction (ADR). These ADRs may be mild but, too often, they can cause serious injury and even death. The statistics on ADRs are alarming.
- There are over two million serious ADRs each year.
- ADRs account for approximately 100,000 deaths annually.
- ADRs are the fourth leading cause of death
- One out of five injuries or deaths to hospitalized patients each year are caused by ADRs.
- More drugs than ever before are being used. Sixty-four percent of all patient visits to a physician result in one or more prescriptions.
- In 2000, 2.8 billion prescriptions were filled. That comes out to about 10 prescriptions for every person in the U.S.
- The rate of adverse drug reactions increases exponentially when a patient is taking four or more medications.
Drug-drug Interactions
In this case, a drug is considered to be any prescription medication, over-the-counter medication (OTC), vitamin or herbal supplement. A common misconception is that OTC medications are safe for everyone because they can be purchased without a prescription. Another common misconception is that anything “natural” must be harmless. Both OTC medications and natural supplements can cause serious drug interactions in the wrong combinations.Drug-drug interactions can take many forms. In some cases, when two drugs interact, the result may be to increase the effect of one or both drugs. For example, if you are taking a prescription blood thinner, you should not also take aspirin. Separately, they each help prevent heart attacks. Together, they can cause excessive bleeding.
Other times, the result of mixing two drugs may be to weaken the effect of one or both drugs. For example, some antacids can prevent certain medicines (like antibiotics or heart medications) from being absorbed into the blood stream. As a result, the prescription medication may not work as well – or at all.
Drug-food Interactions
We seldom think of food or beverages causing an ADR, however, some drug-food combinations can be dangerous. Two of the most common foods that can sometimes cause problems are grapefruit and dairy products. Grapefruit juice blocks the enzymes that metabolize certain drugs, which in effect makes the drug much more potent than it should be. Dairy products can lessen the effectiveness of certain antiobiotics (particularly tetracycline). [he]Symptoms of an Adverse Drug Reaction Some of the most dangerous ADRs result in a dangerous drop or increase in blood pressure or a fast-paced, irregular heartbeat. More common symptoms include nausea, headache, heartburn or dizziness. Call your doctor or pharmacist if you experience any reaction that seems out of the ordinary to you.Preventing Drug Interactions
There are steps you can take to minimize the chances of an ADR.- Tell your doctor about everything you are taking, including prescription drugs, OTC medications, vitamins and herbal supplements. And don’t forget about medicinal creams and ointments you might be using.
- Be sure you get a consumer information sheet with your prescriptions and read it carefully.
- Read the labels on OTC medications, paying special attention to the “Warnings” section.
- Before you buy a new OTC medication, vitamin or herbal supplement, ask your pharmacist if there are any potential drug interactions with the prescriptions you take.
- Use one of the online tools available, like the one described below, that allow you to enter the medications you take and check for possible drug interactions.
Checking for Possible Drug Interactions
I tested several websites offering tools to check for drug interactions. Of the sites I visited, IQhealth offered the widest range of reports and the most comprehensive list of possible interactions. IQhealth provides the Drug Information Site, which allows you to search for information about a specific drug or for interactions between drugs. Below are lists of the reports you can get on this site.Search For Drug Information
- Leaflet
- Pregnancy
- Lactation
- Side Effects
- Pharmacology
- Warnings
- Interactions (both drug and food interactions)
- Duplications
- Allergic Reactions
Sources: U.S. Food and Drug Administration, Center for Drug Evaluation and Research; BeMedWise – Promoting the Wise Use of OTC Medications
