Many dietary supplements can interact with prescription medications, either reducing their effectiveness or increasing the risk of serious side effects.
For that reason, it is always recommended to consult a doctor or pharmacist before starting a new dietary supplement, according to Verywell Health.
Vitamin B6 and levodopa
Vitamin B6 can reduce the effectiveness of levodopa, which is used to treat Parkinson's disease.
However, people taking certain forms of levodopa may also develop a vitamin B6 deficiency. Therefore, supplements should only be taken after consulting a doctor.
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Vitamin K and warfarin
Vitamin K can make blood-thinning medications such as warfarin less effective.
This applies both to vitamin K supplements and to significantly increasing the consumption of foods that are high in vitamin K.
Iron or calcium and thyroid medication
Iron and calcium can make it more difficult for the body to absorb thyroid medication such as levothyroxine.
These products should therefore be taken at least four hours apart.
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Vitamin C and antacids
Vitamin C can increase the absorption of aluminum from certain antacids used to treat heartburn and acid reflux.
To reduce the risk, the two should be taken at least two hours apart.
Vitamin E and blood thinners
Vitamin E can increase the risk of bleeding in people taking blood-thinning medications such as warfarin.
For this reason, the supplement should only be used after consulting a healthcare professional.
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St. John's wort and various medications
St. John's wort can interact with a wide range of medications, including antidepressants, birth control pills, and blood thinners.
The combination can make these medications less effective or lead to harmful effects.
Goldenseal and blood thinners
Goldenseal can interact with medications used to prevent blood clots.
It may increase the risk of bleeding and bruising, which is why this combination is often discouraged.
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Ginkgo biloba and blood thinners
Like goldenseal, ginkgo biloba can increase the risk of bleeding when taken together with blood-thinning medications such as warfarin or aspirin.
Licorice root and diuretics
Licorice root supplements can worsen the side effects of diuretics and medications used to treat high blood pressure.
Among other effects, this may lead to potassium imbalances or changes in blood pressure.
The right timing can reduce problems
The timing of medications and dietary supplements can make a significant difference.
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As a general rule, it is recommended to leave at least two hours between taking dietary supplements and medications, although some medications require even longer intervals.
Talk to your doctor
Healthcare professionals can provide guidance on which combinations should be avoided and how dietary supplements can be used as safely as possible.
It is recommended to inform your doctor about any new products you are considering taking.
Your pharmacist can help
Pharmacists have access to databases that can identify potential interactions between medications and dietary supplements.
They can also provide advice on dosage, timing, and possible alternatives.