Newswise — Cardiovascular medications help to prevent heart attack and stroke, saving many people from the number-one killer in the United States. But taking certain over-the-counter drugs or herbal remedies along with them can cause the prescribed cardiovascular drugs to lose their effectiveness or to increase their potency in ways that can be beneficial or harmful.
That's why it is vital for patients to tell their doctors all the medications and herbal products they are taking, says Wei Lau, M.D., clinical associate professor of anesthesiology who directs adult cardiac anesthesia at the University of Michigan Health System.
"It is very important for you to inform your physician of over-the-counter medications, herbal medications and prescribed medications because of the potential drug to drug interaction or herbal to drug interaction," he says.
In particular, he says people should be aware of the interaction between two common, over-the-counter painkiller drugs, and between a popular blood-thinning drug and an herbal remedy.
Estimates show that about 30 percent of the U.S. population takes some form of cardiovascular drugs, such as blood pressure-reducing and cholesterol-lowering medications, Lau says.
"With all these patients taking cardiovascular medications, a majority of them do inform their physicians of all the medications they're taking. But not all of them do," Lau says.
When taking aspirin to prevent heart attacks or strokes, he says, people should be aware that ibuprofen and some other painkillers called non-steroidal anti-inflammatories will eliminate the protective effect of aspirin.
He also notes that his recent research indicates that the popular herbal remedy St. John's wort, commonly used for the treatment of depression, appears to amplify the action of the blood-thinning drug clopidogrel, sold as Plavix.
When ibuprofen or other non-steroidal anti-inflammatories have to be taken with aspirin due to chronic pain, Lau says, physicians may initially substitute acetaminophen, sold as Tylenol which doesn't take away the heart-protecting effect of aspirin. Alternatively, ibuprofen or non-steroidal anti-inflammatories and aspirin can be administered at different times of the day to ensure that the protective aspects of the aspirin is not taken away.
Lau has been studying how Plavix, which prevents heart attacks or strokes by keeping the platelets in the blood from sticking together, is affected by the herbal remedy St. John's wort, which is marketed as an antidepressant and mood enhancer, in subjects who inherently do not respond to Plavix. Recently, he and his colleagues reported the combination makes the blood even thinner than with Plavix alone.
Lau and his colleagues caution that a potential for an increased risk of bleeding may occur among patients who normally respond to Plavix, and who currently are taking both this prescription medication and St. John's wort.
"If Plavix is effectively preventing the platelets in your blood stream from sticking together," Lau says, "you should not be taking St. John's wort."
But it also means that patients who are known to be resistant to Plavix " which Lau and other researchers outside of UMHS have found is about 28 percent of the population " may be able to enhance the effect of the medication by taking St. John's wort. More studies are needed, he says.
Facts about drug interactions:"¢ A drug interaction is a change in the effect of a drug caused by another substance, such as another drug, herbal remedies, food or alcohol."¢ The interaction can alter the helpful effects of a drug or a drug's side effects."¢ In addition to telling the doctor about other drugs they are taking, patients also should tell their health care providers and pharmacists about herbal products they are taking."¢ Taking ibuprofen (sold as Advil and Motrin) and other non-steroidal anti-inflammatory drugs (NSAIDs) can reduce the helpful effects of asprin. NSAID painkillers include naproxen (sold as Aleve) and Celebrex."¢ In addition to medications and herbal products, food and beverages " such as grapefruit juice " can also interfere with the effectiveness of medications.
For more information, visit these web sites:
U-M Health Topics A-Z, Drug interactions: http://www.med.umich.edu/1libr/aha/aha_drugintr_sha.htm
U-M Health Topics A-Z, What to ask your doctor: http://www.med.umich.edu/1toolbar/visinfo/info05.htm
U-M news release, Herbal remedy St. John's wort amplifies effect of blood-thinning drug Plavix, U-M study suggests: http://www.med.umich.edu/opm/newspage/2005/stjohnwort.htm
FDA, Center for Drug Evaluation and Research, Drug Interactions:http://www.fda.gov/cder/consumerinfo/druginteractions.htm
FDA, Be an Active Member of Your Health Care Team: http://www.fda.gov/cder/consumerinfo/active12panelEng.htm
Written by Katie Gazella
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