Tips to Avoid Problems
There
are lots of things you can do to take prescription or over-the-counter
(OTC) medications in a safe and responsible manner.
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Always read drug labels carefully.
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Learn about the warnings for all the drugs you take.
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Keep medications in their original containers so that you can easily identify them.
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Ask
your doctor what you need to avoid when you are prescribed a new
medication. Ask about food, beverages, dietary supplements, and other
drugs.
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Check with your doctor or pharmacist before taking an OTC drug if you are taking any prescription medications.
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Use one pharmacy for all of your drug needs.
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Keep all of your health care professionals informed about everything that you take.
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Keep
a record of all prescription drugs, OTC drugs, and dietary supplements
(including herbs) that you take. Try to keep this list with you at all
times, but especially when you go on any medical appointment. The Food
and Drug Administration (FDA) has a Web site where you can get more
information and download a sample medicine record: www.fda.gov/cder/consumerinfo/my_medicine_record.htm
People
often combine foods. For example, chocolate and peanut butter might be
considered a tasty combination. But eating chocolate and taking certain
drugs might carry risks. In fact, eating chocolate and taking monoamine
oxidase (MAO) inhibitors, such as Nardil (phenelzine) or Parnate
(tranylcypromine), could be dangerous.
MAO inhibitors
treat depression. Someone who eats an excessive amount of chocolate
after taking an MAO inhibitor may experience a sharp rise in blood
pressure.
Other foods that should be avoided when
taking MAO inhibitors: aged cheese, sausage, bologna, pepperoni, and
salami. These foods can also cause elevated blood pressure when taken
with these medications.
There are three main types of drug interactions:
"Consumers
should learn about the warnings for their medications and talk with
their health care professionals about how to lower the risk of
interactions," says Shiew-Mei Huang, Ph.D., deputy director of the
Office of Clinical Pharmacology in FDA's Center for Drug Evaluation and
Research (CDER).
Drugs with Food and Beverages
Consequences
of drug interactions with food and beverages may include delayed,
decreased, or enhanced absorption of a medication. Food can affect the
bioavailability (the degree and rate at which a drug is absorbed into
someone's system), metabolism, and excretion of certain medications.
Examples of drug interactions with food and beverages …
Alcohol:
If you are taking any sort of medication, it's recommended that you
avoid alcohol, which can increase or decrease the effect of many drugs.
Grapefruit juice:
Grapefruit juice is often mentioned as a product that can interact
negatively with drugs, but the actual number of drugs the juice can
interact with is less well-known. Grapefruit juice shouldn't be taken
with certain blood pressure-lowering drugs or cyclosporine for the
prevention of organ transplant rejection. That's because grapefruit
juice can cause higher levels of those medicines in your body, making
it more likely that you will have side effects from the medicine. The
juice can also interact to cause higher blood levels of the
anti-anxiety medicine Buspar (buspirone); the anti-malaria drugs
Quinerva or Quinite (quinine); and Halcion (triazolam), a medication
used to treat insomnia.
Licorice: This
would appear to be a fairly harmless snack food. However, for someone
taking Lanoxin (digoxin), some forms of licorice may increase the risk
for Lanoxin toxicity. Lanoxin is used to treat congestive heart failure
and abnormal heart rhythms. Licorice may also reduce the effects of
blood pressure drugs or diuretic (urine-producing) drugs, including
Hydrodiuril (hydrochlorothiazide) and Aldactone (spironolactone).
Chocolate:
MAO inhibitors are just one category of drugs that shouldn't be
consumed with excessive amounts of chocolate. The caffeine in chocolate
can also interact with stimulant drugs such as Ritalin
(methylphenidate), increasing their effect, or by decreasing the effect
of sedative-hypnotics such as Ambien (zolpidem).
Drugs with Dietary Supplements
Research
has shown that 50 percent or more of American adults use dietary
supplements on a regular basis, according to congressional testimony by
the Office of Dietary Supplements in the National Institutes of Health.
The law defines dietary supplements in part as
products taken by mouth that contain a "dietary ingredient." Dietary
ingredients include vitamins, minerals, amino acids, and herbs or
botanicals, as well as other substances that can be used to supplement
the diet.
Examples of drug interactions with dietary supplements …
St. John's Wort (Hypericum perforatum):
This herb is considered an inducer of liver enzymes, which means it can
reduce the concentration of medications in the blood. St. John's Wort
can reduce the blood level of medications such as Lanoxin, the
cholesterol-lowering drugs Mevacor and Altocor (lovastatin), and the
erectile dysfunction drug Viagra (sildenafil).
Vitamin E:
Taking vitamin E with a blood-thinning medication such as Coumadin can
increase anti-clotting activity and may cause an increased risk of
bleeding.
Ginseng: This herb can
interfere with the bleeding effects of Coumadin. In addition, ginseng
can enhance the bleeding effects of heparin, aspirin, and nonsteroidal
anti-inflammatory drugs such as ibuprofen, naproxen, and ketoprofen.
Combining ginseng with MAO inhibitors such as Nardil or Parnate may
cause headache, trouble sleeping, nervousness, and hyperactivity.
Ginkgo Biloba:
High doses of the herb Ginkgo biloba could decrease the effectiveness
of anticonvulsant therapy in patients taking the following medications
to control seizures: Tegretol, Equetro or Carbatrol (carbamazepine),
and Depakote (valproic acid).
Drugs with Other Drugs
Two
out of every three patients who visit a doctor leave with at least one
prescription for medication, according to a 2007 report on medication
safety issued by the Institute for Safe Medication Practices. Close to
40 percent of the U.S. population receive prescriptions for four or
more medications. And the rate of adverse drug reactions increases
dramatically after a patient is on four or more medications.
Drug-drug
interactions have led to adverse events and withdrawals of drugs from
the market, according to an article on drug interactions co-authored by
Shiew-Mei Huang, Ph.D., deputy director of FDA's Office of Clinical
Pharmacology. The paper was published in the June 2008 issue of the
Journal of Clinical Pharmacology.
However,
market withdrawal of a drug is a fairly drastic measure. More often,
FDA will issue an alert warning the public and health care providers
about risks as the result of drug interactions.
Examples of drug interactions with other drugs …
Cordarone (amiodarone):
FDA issued an alert in August 2008, warning patients about taking
Cordarone to correct abnormal rhythms of the heart and the
cholesterol-lowering drug Zocor (Simvastatin). Patients taking Zocor in
doses higher than 20 mg while also taking Cordarone run the risk of
developing a rare condition of muscle injury called rhabdomyolysis,
which can lead to kidney failure or death. "Cordarone also can inhibit
or reduce the effect of the blood thinner Coumadin (warfarin)," said
Huang. "So if you're using Cordarone, you may need to reduce the amount
of Coumadin you're taking."
Lanoxin (digoxin):
"Lanoxin has a narrow therapeutic range. So other drugs, such as Norvir
(ritonvair), can elevate the level of Lanoxin," says Huang. "And an
increased level of Lanoxin can cause irregular heart rhythms." Norvir
is a protease inhibitor used to treat HIV, the virus that causes AIDS.
Antihistamines:
Over-the-counter (OTC) antihistamines are drugs that temporarily
relieve a runny nose, or reduce sneezing, itching of the nose or
throat, and itchy watery eyes. If you are taking sedatives,
tranquilizers, or a prescription drug for high blood pressure or
depression, you should check with a doctor or pharmacist before you
start using antihistimines. Some antihistamines can increase the
depressant effects (such as sleepiness) of a sedative or tranquilizer.
The sedating effect of some antihistamines combined with a sedating
antidepressant could strongly affect your concentration level.
Operating a car or any other machinery could be particularly dangerous
if your ability to focus is impaired. Antihistamines taken in
conjunction with blood pressure medication may cause a person's blood
pressure to increase and may also speed up the heart rate.
This article appears on FDA's Consumer Health Information Web page (www.fda.gov/consumer), which features the latest updates on FDA-regulated products. Sign up for free e-mail subscriptions at www.fda.gov/consumer/consumerenews.html.
For More Information
FDA's Drug Development and Drug Interactions Web site
www.fda.gov/cder/drug/drugInteractions/default.htm
Consumer Education: Ensuring Safe Use of Medicine
www.fda.gov/cder/consumerinfo/ensuring_safe_use_text.htm
MedWatch
www.fda.gov/medwatch/
Preventable Adverse Drug Reactions: A Focus on Drug Interactions
www.fda.gov/cder/drug/drugReactions/default.htm
released on Nov 28, 2008 by FDA
