Can Supplements Interact With Prescription Medications?

Taking prescription drugs? Be careful with vitamins and supplements.

There seems to be a supplement for everything these days. From formulas to boost brain health to ones that deliver healthier looking skin and nails, supplements seem to do it all. They may be a great way to help you feel your best. But when you’re taking prescription medications, understanding how they may react with your supplements is key.

What are supplements?

“Supplements are over-the-counter products you add to your diet,” says Dominic Maneval, PharmD, specialty clinical pharmacist at Geisinger. “They offer a variety of health benefits.”

Supplements contain a variety of ingredients, including:

Vitamins, like vitamin C
Minerals
Herbs
Amino acids
Enzymes

Can you take supplements with medicine?

You can take supplements alongside prescription medication. But you must be careful.

“Supplements can interact with your medicine in unexpected ways,” Dr. Maneval says. They do this through a few different methods.

Changing breakdown time

Certain supplements can affect how your body breaks down or absorbs medicine. “This may result in having too much or not enough medicine in your body at one time,” says Dr. Maneval. “And that can result in health conditions not being as well controlled as they should be.”

It can also lead you to feel more severe side effects.

Unpredictable side effects

The combination of supplements and prescriptions can change the concentration of medicine in your body. That change can lead to unpredictable or unusual side effects. And for some, those side effects can be serious.

For example, if you take medicine to lower blood pressure, some supplements can make it go too low. That drop in blood pressure can make you dizzy. You can also feel weak and tired or have nausea and vomiting.

Supplements like milk thistle, an herb commonly used to lower blood sugar, can interact with certain diabetes medicines. That can cause an unsafe drop in blood sugar.

Calcium and magnesium can also reduce the effectiveness of certain antibiotics.

“Saint John’s Wort can also make birth control less effective,” says Dr. Maneval.

Increased bleeding risk

Taking blood thinners? You may want to rethink taking some of those supplements. Several herbal supplements can thin the blood, including:

Vitamin E
Turmeric
Gingko biloba
Fenugreek
Melatonin

Taking them with blood thinners can increase your bleeding risk, especially during surgery. That higher risk of bleeding can also increase your likelihood of having a stroke.

Who’s at risk of an interaction?

“Anyone who takes supplements is at risk of having an interaction,” Dr. Maneval notes. However, if you metabolize medicine differently than others, your risk may be higher. And certain groups are more likely to have an interaction, including:

Children
Pregnant or breastfeeding women
Those 65 and older
People who take multiple medications at once
People who have recently had surgery

A little education goes a long way

To avoid potential interactions, start by talking to your healthcare provider about the supplements you take. They can help identify things to avoid. They can also make recommendations for alternative medicines. Or they may suggest stopping your supplements temporarily.

It’s also important to note that supplements aren’t a substitute for prescription medication. “If you’re thinking about using a supplement in place of medicine, always talk to your healthcare provider first,” Dr. Maneval stresses. They can help you build a treatment plan tailored to your individual needs. So you can feel your best, no matter what you’re taking.