There can be some interactions or potential interactions between conventional medicines and herbal treatments and food supplements. It is particularly important to be careful when combining supplements such as iron, potassium, magnesium and zinc with conventional treatments as some drugs will increase their excretion and some will reduce excretion, making toxicity a possibility. Other substances can also interact with the uptake of the medication. It is important to discuss with your coordinating therapist which supplements, herbals or medications might be of benefit in your personal strategy.
Most conventional medicines that treat hypertension should not be used with the African herb yohimbe (yohimbine) which is used generally to increase libido. There is information online stating that Yohimbine may reduce blood pressure but all of the studies that Patient QI found showed that it led to increased blood pressure.
Diuretics can increase urinary excretion of potassium and sodium. Potassium- sparing diuretics increase urinary excretion of sodium but also reduce excretion of magnesium so care must be taken with magnesium supplements.
Potassium-sparing diuretics can increase or decrease Zinc excretion depending on the brand of diuretic. Amiloride decreases zinc excretion, and can lead to a build up of zinc and zinc toxicity. Triamterene increases zinc secretion.
Calcium supplements can decrease the blood levels of beta blockers.
Coenzyme Q10 is important in heart muscle and other tissues for producing energy. It is particularly important for healthy heart functioning. Many high blood pressure treatments such as beta blockers, especially propanolol inhibit the enzymes that use CoQ10. Supplements of CoQ10 are important in elderly patients or patients deficient in CoQ10 who are taking hypertensive drugs.
Iron supplements can affect the absorption of ace inhibitors. Iron can bind to the Ace inhibitor and reduce absorption of both the drug and the iron.
Ace inhibitors bind to zinc and can lead to zinc deficiency.
Ace inhibitors cause retention of potassium so should not be combined with potassium supplements except on the advice of a qualified practitioner.
Calcium Channel Blockers
Calcium and calcium salts taken orally can interfere with the action of calcium channel blockers as can Vitamin D.
Grapefruit juice has an effect that slows down the metabolism of many drugs and this can result in higher levels of the drug in the bloodstream. This has been shown to be true for some calcium channel blockers.
Peppermint oil may have some calcium channel blocking and could add to make the calcium channel blockers action but also could compete. The studies on this are unclear.
Vasodilators such as hydralazine may interfere with Vitamin B6 activity resulting in low Vitamin B6 levels. However taking Vitamin B6 supplements may reduce the therapeutic effect of the vasodilator.
Capsaicin, the hot ingredient in chilli peppers and cayenne pepper has been known to cause acute hypertensive crisis and patients should be aware of this.