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How to Avoid Dangerous Interactions from Supplements and Medication

You might take supplements to try to improve your heart health, boost your immune system, protect your joints or make up for any nutrients you might be missing, even if you’re eating a balanced diet. 

Even though you can buy supplements over the counter, and they might be made from natural ingredients, you should still be sure to tell your health care provider which ones you are taking. That’s because some supplements can interact with prescription medications. And your prescription medications are vital in keeping you healthy and ensuring your medical conditions are managed properly.

“Many vitamins or supplements can interact with prescription medications,” said Sophia Galloway, PharmD, a pharmacist with Banner – University Medicine. “These interactions could increase the concentration of the prescription medication, which can increase your risk of side effects. They could also make a prescription medication less effective, so it doesn’t work properly or at all. That can be deadly, depending on the medication.”

Here are a few of the supplements that could possibly interact with prescription drugs. These aren’t the only supplements that could cause issues, so be sure to talk to a health care provider about any supplements you take.

1. St. John’s wort

Why you might use it: People often turn to St. John’s wort to help treat depression and other mood disorders.

Be careful if: You take certain medications since St. John’s wort can interact with many different prescriptions. For example, it can make blood thinners less effective, and interact with medications for seizures, cholesterol and depression.

2. Ginkgo biloba

Why you might use it: Ginkgo biloba is a popular supplement for anxiety and memory problems.

Be careful if: You also use blood thinners (anticoagulants) such as warfarin (Coumadin), since ginkgo biloba increases your risk of bleeding.

3. Ginseng

Why you might use it: People often try ginseng to improve stamina, memory and immunity. 

Be careful if: You take blood thinners, stimulants, antidepressants, immunosuppressant drugs or medications to treat diabetes or high blood pressure. There’s a possibility that ginseng will interact with them.

4. Garlic

Why you might use it: You might try garlic to help lower blood pressure or cholesterol levels.

Be careful if: You take blood thinners or medication for HIV/AIDS, high blood pressure or diabetes since garlic could change how these medications work.

5. Vitamin K

Why you might use it: Some people use vitamin K in the hopes that it will keep their bones stronger.

Be careful if: You take blood-thinning medications. Vitamin K might make them less effective.

6. Calcium and iron

Why you might use them: Calcium is one of the most common supplements. Mainly used to help build and maintain bone strength, calcium is also used by your heart, muscles and nerves. Iron helps your blood carry oxygen to your body, and deficiencies are common. About 10% of women have low iron levels.

Be careful if: You take thyroid medication, since these supplements can make your body absorb it less effectively. You may not need to avoid them, but it’s best to take the supplements and your thyroid medication separately. These supplements may also make some antibiotics, including ciprofloxacin, less effective.

7. Hawthorn

Why you might use it: Hawthorn is a popular herbal remedy for heart health.

Be careful if: You take medication for high blood pressure. Hawthorn can interact with it and cause dangerously low blood pressure.

8. Herbal teas

Why you might use them: You might drink herbal teas because you find them warm and comforting and you like the fact that they don’t contain caffeine. And some types might help support your immune system or lower your blood pressure.

Be careful if: You don’t consider herbal teas to be supplements. While they may seem harmless, certain types can cause medication interactions. For example, chamomile tea, which can promote relaxation, might increase the effects of sedative medications you’re taking.

What to do

“Never start a new vitamin or supplement without first speaking to your doctor or pharmacist,” Dr. Galloway said.

Make a list of all the supplements and medications you take and review it regularly with your health care provider. It can be helpful to create a list on your phone so you can update it quickly and you don’t forget to bring it to your appointments. You can discuss possible interactions with your provider and make informed treatment decisions. 

Be sure to talk to your provider about the pros and cons of taking supplements, and look to reliable, evidence-based sources of information when you’re researching supplements. Don’t rely only on word-of-mouth or online forums.

“Keep in mind that even if a supplement is safe, it may not have any evidence for being effective — there’s a lot of money, marketing and social media promotion behind them,” Dr. Galloway said. “Talk to your doctor or pharmacist — they have reputable sources where they can look up the research behind supplements.”

The bottom line

If you’re thinking about taking supplements or are already taking them, talk to your health care provider about your medications. Many supplements can cause dangerous interactions with prescription medicines. When you know your risks, you can work with your provider to make informed decisions about your health.

If you would like to talk about possible supplement interactions with a health care provider who can guide you on your journey, reach out to Banner Health.

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