How does food interact with your medications?

Whenever you pick up a prescription medication, you may notice little stickers on the bottle that say “Take on an empty stomach” or “Take with food.” You may also find similar instructions on the nonprescription (over-the-counter) Drug Facts label as well.

Most people understand that some medications can interact with other medications, but did you know that food can affect how your medication works as well? It's important to understand this issue so you can get the most out of your treatment.

When you swallow a medication, it goes into your stomach and is absorbed into your body. Certain medications should not be taken with food because food can decrease or delay the amount of drug that gets absorbed. However, other medications need to be taken with food, or certain kinds of food, in order to work better or to have fewer side effects.

Some medications are not absorbed well if there is food in your stomach, making the medication less effective. It is best to take the following medicines on an empty stomach:

• Thyroid replacement medications (e.g., levothyroxine [Synthroid]),
• Medications used to treat bone loss (e.g, alendronate [Fosamax], ibandronate [Boniva], residronate [Boniva]), and
• Proton pump inhibitors used to treat stomach problems (e.g., omeprazole [Prilosec], lanszoprazole [Prevacid], pantoprazole [Protonix], or esomeprazole [Nexium, Vimovo].

A common side effect of some medications is an upset stomach. Non-steroidal anti-inflammatory medications like ibuprofen (Advil, Motrin), naproxen (Aleve), or aspirin (Bayer Aspirin, Alka-Seltzer) are examples of medicines that may cause an upset stomach. These medications may have fewer side effects if they are taken with food. If your prescription or over-the-counter product label does not encourage you to take your medication with food but you have an upset stomach, talk to your pharmacist about whether it is safe to take your medications with food.

Some medications only interact with certain types of foods and can change how your medications work. Below are a few common foods that may affect some medications.

• Calcium: Dairy products or other foods that are high in calcium can reduce absorption and therefore decrease the effectiveness of the some antibiotics such as ciprofloxacin (Cipro, Proquin XR Extended-release Tablets), levofloxacin (Levaquin), doxycycline (Doryx, Oracea, Periostat, Vibra-Tabs, Vibramycin), and minocycline (Minocin). These medications should be taken two hours before or six hours after eating foods high in calcium.
• Vitamin K: Green leafy vegetables that have high vitamin K content, such as spinach, kale, and romaine lettuce, can affect the “blood thinning” medication warfarin (Coumadin). Vitamin K reverses the effects of warfarin and increases blood clotting. You do not need to avoid eating these foods while on warfarin—just stay consistent with the amount you eat per week.
• Grapefruit: Grapefruit and grapefruit juice can decrease the ability of the body to process certain medications which can cause side effects from increased amounts of the drug remaining in your body. Avoid drinking grapefruit juice or eating grapefruit if you are taking atorvastatin (Lipitor), simvastatin (Zocor, Vytorin), or lovastatin (Mevacor) to treat high cholesterol, or if you are taking warfarin.
• Tyramine: Cheese, dried fruit, or meat that is smoked, aged, improperly stored, or spoiled are high in tyramine which can cause side effects when taken with certain medications called monoamine oxidase inhibitors. Medications used to treat depression such as phenelzine (Nardil) and tranylcypromine (Parnate) and the antibiotic linezolid (Zyvox) may interact adversely with foods high in tyramine.

How can you tell if food will affect your medication? Be sure to read the little stickers that are attached to your medication bottles, the patient information that comes with your medication, or the Drug Facts label on over-the counter medications. All of these resources have information about how food affects your medications.

And, of course, if you are ever unsure about whether you can take a medication with food, just ask your pharmacist.

Related questions

• Can you use limes or lime juice while taking statin drugs (i.e. atorvastatin)?
• Why do you have to avoid grapefruit when taking Latuda?
• Can I drink grapefruit juice with simvastatin?