The Most Common Food and Drug Interactions

You may not realize that certain foods or drinks can affect how your medication works. Some foods or drinks may need to be avoided altogether for your medication to work correctly.

You may know to ask your pharmacist if your medication should be taken with or without food, but did you know that certain foods may need to be avoided altogether? Food can interact with certain drugs by either causing too much or too little of the drug to exert its effect in the body. This can lead to unwanted side effects, toxic levels of a drug in the body, or little to no effect of the drug. Learn about the most common food and drug interactions below.


Alcohol can be a problem when taken with your medications for a number of reasons. First, alcohol itself is considered a drug and as such, has side effects. It can impair your judgment, cause drowsiness or sedation, and affect your coordination. For medications that have similar side effects, this can be a problem. Alcohol is also metabolized by the liver. If you drink three or more alcoholic drinks a day, taking medications that are also metabolized by the liver can put you at an increased risk of liver damage.

Some medications that alcohol can interfere with include:


Antihistamines are used to treat allergies and can cause an increase in drowsiness. Claritin (loratadine), Zyrtec (cetirizine), Benadryl (diphenhydramine), and Allegra (fexofenadine) are all in the class of antihistamines.

Pain relievers:

Tylenol (acetaminophen) is metabolized by the liver like alcohol. Ask your doctor about taking this medication if you drink three or more alcoholic beverages a day. Non-steroidal anti-inflammatory drugs (NSAIDS) like Motrin (ibuprofen), Aleve (naproxen), or aspirin can cause stomach bleeds. Again, drinking more than three alcoholic drinks a day can increase this bleeding risk.

Narcotic pain relievers:

These pain relievers cause a significant amount of drowsiness on their own. Taking them with alcohol can cause increased drowsiness, respiratory depression (breathing problems), or even death. You should avoid alcohol when taking any narcotic pain relievers such as codeine, hydrocodone, or morphine, for example.


Metronidazole is used for certain types of infections and alcohol should not be consumed at all when you are on this medication. Taking alcohol with this medication can lead to nausea, severe vomiting, flushing, headache, and stomach cramps. Wait at least one full day after finishing this medication before drinking any alcohol.

Psychiatry medications:

Drugs used to treat depression, anxiety, bipolar disease, and other psychiatric conditions will most likely have an interaction with alcohol. Check with the pharmacist at your community pharmacy before combining these drugs with alcohol, which could lead to significant drowsiness or sedation.

Grapefruit juice

You may be aware that grapefruit juice should be avoided while taking many different types of medications. Grapefruit juice can either interfere with the metabolism of the drug and cause too high of a level of the drug in the body, or it can block the drug from even being absorbed from the gastrointestinal tract, making the drug ineffective. Some common drugs that grapefruit juice may interfere with include:

  • Statin drugs for cholesterol like Zocor (simvastatin), Crestor (rosuvastatin), or Lipitor (atrovastatin)
  • Blood pressure medicine Procardia (nifedipine)
  • Organ transplant anti-rejection drug Neoral or Sandimmune (cyclosporin)
  • Antiarrhythmic drug Pacerone or Cordarone (amiodarone)
  • Antibiotic Erythromycin
  • Antidepressant Zoloft (sertraline)


Foods high in potassium, such as bananas, watermelon, potatoes, avocados, coconut water, green leafy vegetables, salt substitutes, and beans can interact with medications that can retain potassium in the body. One class of drugs used to treat high blood pressure, ACE inhibitors, can interact with foods high in potassium, potentially raising your potassium levels too high. Some examples of ACE inhibitors include captopril, enalapril, and lisinopril. Potassium-sparing diuretics (water pills) such as triamterene and spironolactone may have this same reaction with potassium-rich foods.

Vitamin K

Vitamin K plays an important part in your body’s ability to clot. If you are taking a blood thinner like Coumadin (warfarin), keeping a consistent diet of foods known to be high in vitamin K is important. Suddenly increasing your intake of foods rich in vitamin K could lead to the drug coumadin, or its generic medicine warfarin, not working as effectively. Foods known to be high in vitamin K include broccoli, cabbage, spinach, collard greens, turnip greens, kale, and Brussel sprouts.


Tyramine is found naturally in aged or fermented foods such as aged cheeses, dried sausage or salami, pickled, fermented, or smoked foods, excessive amounts of chocolate, yeast extract, and sauerkraut. If you are taking an antidepressant found in the monoamine oxidase inhibitors (MAOI) class such as phenelzine or tranylcypromine, you should not consume any foods containing tyramine. Other medications that can interact with tyramine-rich foods include Zyvox (linezolid) and isoniazid.


Calcium-rich foods such as milk, yogurt, cheese, calcium supplements, and calcium antacids can interact with certain antibiotics. Some antibiotics that calcium may interfere with include tetracycline, doxycycline, and Cipro (ciprofloxacin). Taking foods or supplements either 1 hour before or 2 hours after taking the antibiotic will allow the drug to still be absorbed.

Taking Medications With or Without Food

Sometimes the question is not what foods you should avoid, but does the medication need to be taken on an empty or full stomach. Below are some examples of medications that should either be taken with or without food.

  • NSAIDS like Motrin (ibuprofen), Aleve (naproxen), and Celebrex (celecoxib) should be taken with food
  • ACE inhibitors captopril and moexipril should be taken one hour before meals
  • Beta-blocker carvedilol should be taken with food
  • Heart medication Lanoxin (digoxin) should be taken either one hour before or two hours after eating food
  • Proton pump inhibitors like omeprazole, lansoprazole, and pantoprazole, in general, should be taken one hour before eating
  • Thyroid medication like Synthroid (levothyroxine) should be taken in the morning on an empty stomach

It is important to realize that there are many foods that may interact with your medications. Whether the medication is a compound medication or manufactured medication, contact Smith-Caldwell drug store, your community pharmacy, to check on these and other food-drug interactions.