7 Medicines & Supplements You Shouldn’t Mix with Juice

If you take supplements or medications in the morning, you may be reaching for a glass of your favorite juice to make taking them a bit easier. This might seem like a good move (we all need our vitamin C, after all!). But this practice can result in interactions that can negatively impact the effectiveness of your medications or supplements. Or worse, lead to dangerous consequences. 

Here’s what you need to know about the biggest offenders.

1.  Fluoroquinolone Antibiotics

If you’re taking fluoroquinolone antibiotics, like ciprofloxacin, levofloxacin or moxifloxacin, you might want to temporarily reevaluate your juice habit.  This group of commonly prescribed antibiotics can interact with juices containing calcium, iron or magnesium, says Freddy Alaniz, Pharm.D. These minerals can bind with fluoroquinolones, forming complexes called chelates. “When these complexes form in the stomach or intestines, the drug becomes poorly soluble and poorly absorbed, leading to markedly reduced bioavailability and treatment failure,” explains Alaniz. That can spell trouble if you chase them down with most kinds of juice, especially iron-rich prune juice or calcium-fortified orange juice. 

“Always take [antibiotics] with plain water for best absorption,” says Alaniz. However, if you do drink juice during the day, Alaniz recommends taking fluoroquinolones at least two hours before or four to six hours afterward.

2. Iron Supplements

Health care providers often recommend iron supplements during pregnancy and for people with iron deficiency. They may also be beneficial for those who follow a strict plant-based eating plan. However, iron supplements have known interactions with compounds and nutrients in some juices. 

“Iron supplements should not be taken with green juices because the polyphenols can bind to iron in the GI tract and prevent absorption,” says Syrah McGivern, M.S., RD, LDN. Because calcium inhibits iron absorption, iron supplements should also not be mixed with calcium-fortified juices, such as calcium-fortified orange juice. If you choose to drink calcium-fortified or green juices when taking an iron supplement, it’s recommended to separate the supplement from juice by at least two hours to ensure optimal iron absorption.

3. Fexofenadine (Allegra)

“Fexofenadine (Allegra) can interact with acidic juices, such as apple, orange and grapefruit juice,” says Anna Rosell, RDN. “Citrus juice significantly reduces fexofenadine’s effectiveness by blocking the transporters in the small intestine that are necessary for absorption into the bloodstream.” Rosell further explains that when the transporters are blocked, less of the medication is absorbed, resulting in reduced effectiveness.  

If you like to drink citrus or apple juice, the Asthma and Allergy Foundation of America recommends waiting two hours before or after taking Allegra.

4. Proton Pump Inhibitors (PPIs)

Proton pump inhibitors (PPIs) are often used to treat gastroesophageal reflux disease (GERD), acid reflux, and stomach or intestinal ulcers. These medications work by lowering stomach acid. They are available over-the-counter as omeprazole (Prilosec), esomeprazole (Nexium) and lansoprazole (Prevacid), and also by prescription.

However, they can only do their job when taken on an empty stomach, ideally at least 30 to 60 minutes before eating or drinking. Regardless of the timing window, there’s some evidence that regularly drinking cranberry or grapefruit juice may reduce their bioavailability. If you drink either of these juices frequently, speak to your health care provider to find out if they might be interfering with your treatment. 

5. Potassium-Sparing Diuretics

Diuretics help your body excrete sodium, so they are often prescribed to help with high blood pressure. However, they can also make your body lose potassium, a mineral that helps regulate blood pressure. Fortunately, some varieties of diuretics, called potassium-sparing diuretics, such as amiloride (Midamor) and spironolactone (Aldactone), are designed to help you excrete sodium but hang on to potassium. 

While that can be beneficial for your blood pressure, consuming too much potassium when taking these medications can lead to dangerously high potassium levels. If you’re taking these meds, your health care provider may already be monitoring your potassium levels. However, you’ll definitely want to avoid juices made with high-potassium fruits, such as bananas, mangos or oranges, as well as vegetable juice blends. 

6. Statins

One of the most well-known drug interactions is between grapefruit juice and a class of cholesterol-lowering medications called statins, like Lipitor (atorvastatin), Mevacor (lovastatin), Crestor (rosuvastatin) and Zocor (simvastatin). Unfortunately, grapefruit juice can reduce the availability of an enzyme that helps break down statins, increasing the medication’s concentration in the bloodstream. That could be dangerous or lead to adverse side effects.

Turns out, grapefruit juice can have this effect on many classes of medications, not just statins. These include some medications used for anxiety, high blood pressure, heart rhythm abnormalities, ulcerative colitis and Crohn’s disease, among others. 

7. Anticoagulants

Anticoagulants are blood thinners that are prescribed for several heart-health issues, including atrial fibrillation, congenital heart defects and heart valve replacements. They are also used to reduce the risk of blood clots after certain types of surgery. Perhaps the most common is warfarin (Coumadin).

Anticoagulants, like warfarin, can block the action of vitamin K, a fat-soluble vitamin involved in the blood clotting process. This doesn’t necessarily mean you need to avoid vitamin K-rich foods and drinks entirely if you’re taking warfarin. However, it is important to keep your vitamin K levels steady so that your health care provider can determine the optimal dose for your needs. If you are taking warfarin and drink juices high in vitamin K, like carrot juice, pomegranate juice or any vegetable juices (especially ones made with leafy greens), it’s critical to let your health care provider know.  

Our Expert Take

A glass of juice can be a quick, convenient and delicious way to work in more nutrients. But if you are taking certain prescription medications, like antibiotics, statins, proton pump inhibitors, potassium-sparing diuretics or warfarin, you may need to avoid or change the timing of when you drink your juice. The same goes for iron supplements, as they may not be fully absorbed when taken with certain types of juice. Interactions between juice and certain medications or supplements can vary from mild to significant, so don’t go it alone. “If patients have any questions about how or when to take a specific medication, they should consult their pharmacist or doctor,” says Alaniz.