"Prescription medications may change the way the body absorbs or utilizes certain micronutrients, raising overall levels, especially if the person is also supplementing with a daily vitamin. And, on the flip side, the daily vitamin, herb or other supplement may impact the effectiveness of the medication. These are called drug-nutrient interactions (DNIs)."
— Brandi Cole, PharmD, pharmacist
at Persona Nutrition
Our team has developed a database of over 2,500 drugs that interact with nutritional supplements. Below we highlight the top eight, based on customer input.
When taken simultaneously with some medications, zinc can bind with the drug in the stomach and form complexes making it more difficult for the body to absorb the medication. This is a common interaction with thyroid medications and certain types of antibiotics.
Vitamin C may increase estrogen levels by altering the way they body metabolizes the hormone. This can increase the side effects a patient may experience in particular with hormone replacement therapy or oral contraceptives containing estrogen.
Patient's using immunosuppressive therapies should consult their health care provider prior to taking any supplement that may stimulate their immune system.
For those taking antihypertensives, garlic supplements may have an additive effect with these prescription drugs and should be avoided.
Because diuretics can decrease blood pressure, when combined with supplements that may also lower blood pressure, diuretics could potentially increase risk for hypotension.
5-HTP is a precursor of serotonin. Combining supplemental 5-HTP with antidepressant medications that increase serotonin levels in the brain could theoretically lead to serotonin syndrome, a dangerous overload of serotonin in the brain. Common side effects of serotonin syndrome include headache, confusion, and loss of muscle coordination, but in severe cases result in irregular heart rhythm or seizure.
Grapefruit can interfere with certain antianxiety medications by altering enzymes responsible for transporting these medications into the blood stream and the breakdown of these medications. This results in increased side effects of antianxiety medications, like prolonged sedation. Grapefruit should be avoided with antianxiety medications to ensure appropriate levels of medications in the blood stream.
Vitamin K is an essential vitamin to promote normal amounts of blood clotting in the body and preventing excessive bleeding. However, when combined, vitamin K can work against these anticoagulant medications and increase the risk for a blood clot.
Certain oral contraceptives can decrease caffeine clearance in the body by up to 65%, which can increase the effects of caffeine in green tea.
Garlic should be avoided with oral contraceptives to ensure the drug is not cleared too quickly from the body, and potentially make the medication less effective.
Spirulina is thought to stimulate the body's immune system. Immunosuppressant therapies, commonly used to treat Crohn's disease and psoriasis, can be less effective if the body's immune system is activated.
Cholesterol lowering medications, called statins, block your body from producing cholesterol. It is thought that using a CoEnzyme Q10 supplement may help relieve muscle discomfort in patients taking a statin therapy.
Preliminary evidence shows that ashwagandha root powder can decrease blood glucose. To avoid an additive effect of blood sugar becoming too low, Ashwagandha should be avoided with those taking blood sugar lowering drugs.
When taken simultaneously, thyroid medications and iron form insoluble complexes in the gastrointestinal tract preventing the absorption of thyroid medication into the blood stream. Iron supplements should be taken at least two hours apart from thyroid medications to ensure complete absorption of the drug.