Don's Home Health Food-Drug Interactions
I recently got a prescription for Ciprofloxacin HCL, a quinolone, an antibiotic for a sinus infection.
The instructions said "Do not take with milk, calcium fortified beverages or yogurt"
It didn't say what time frame constituted "with" (1 hr, 2 hrs, ...)
and "Take 2Hrs before or 12Hrs after antacids, iron, vit/minerals.
It called for a pill every 12 hrs., so if it took it 2 hrs. before vitamins that would be less than 12 hrs after.


Empty Stomach - One hour before eating, or two hours after eating
With - Less than 1 hours before or 2 hours after.

Examples of Food/Drug Interactions

Drug Class

Food that Interacts

Effect of the Food

What to Do

acetaminophen (Tylenol)


Increases risk for liver toxicity

Avoid alcohol

→tetracyclines →Dairy products; iron supplements →Decreases drug absorption →Do not take with milk. Take 1 hour before or 2 hours after food/milk.
→amoxicillin*, penicillin, zithromax, erythromycin →Food →Decreases drug absorption →Take 1 hour before or 2 hours after meals.
* Recomendations at PubMed at the NIH say amoxicillin can be taken with or without food. Follow the directions on your prescription label.
→nitrofurantoin (Macrobid) →Food →Decreases GI distress, slows drug absorption →Take with food or milk.

warfarin (Coumadin)

Foods rich in Vitamin K

Decreases drug effectiveness

Limit foods high in Vitamin K: liver, broccoli, spinach, kale, cauliflower, and Brussels sprouts


phenobarbital, primidone


Causes increased drowsiness

Avoid alcohol

Vitamin C

Decrease in drug effectiveness

Avoid excess vitamin C


griseofulvin (Fulvicin)

High-fat meal

Increases drug absorption

Take with high-fat meal




Increased drowsiness

Avoid alcohol


lovastatin (Mevacor)


Enhances drug absorption

Take with food


felodipine (Plendil), nifedipine

Grapefruit juice

Increases drug absorption

Consult your physician or

Pharmacist before changing diet.


naproxen (Naprosyn),

ibuprofen (Motrin)

→Food or milk

→Decreases GI irritation

→Take with food or milk


→Increases risk for liver

→Damage or stomach bleeding

→Avoid alcohol


spironolactone (Aldactone)


Decreases GI irritation

Take with food


MAO inhibitors:

isocarboxazid (Marplan),

tranylcypromine (Parnate),

phenelzine (Nardil)

Foods high in tyramine: aged cheeses, Chianti wine, pickled herring, Brewer's yeast, fava beans

Risk for hypertensive crisis

Avoid foods high in tyramine

Table 2: Examples of Drug/Nutrient Interactions

Drug Class

Food that Interacts

Effect of the Food

What to Do

Acid Blocker

ranitidine (Zantac),

cimetidine (Tagamet),

famotidine (Pepcid),

nizatidine (Axid)

Vitamin B12

Decrease vitamin absorption

Consult your physician regarding B12 supplementation


cholestyramine (Questran),

colestipol (Colestid)

Fat soluble vitamins

(A, D, E, K)

Decreases vitamin absorption

Include rich sources of these vitamins in the diet



Folic acid, vitamin B12

Decreases vitamin absorption

Consult your physician regarding supplementation


furosemide (Lasix),

hydrochlorothiazide (HCTZ)

Many minerals

Increases mineral loss in urine

Include fresh fruits and vegetables in the diet


fibercon, Mitrolan

Vitamins and minerals

Decreases nutrient absorption

Consult your physician regarding supplementation

Source: FOOD/DRUG and DRUG/NUTRIENT INTERACTIONS: What You Should Know About Your Medications (University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program)


Drug Class

Food that Interacts

Effect of the Food

What to Do

Quinolone Antibiotics (ciprofloxacin, nalidixic acid, cinoxacin) Antacids, iron, vitamins and minerals, may contain aluminum, calcium, iron, lanthanum, magnesium, and/or zinc These elements are cations that may bind to your antibiotic in your digestive tract. This prevents your body from absorbing the antibiotic. Take antibiotic 2 Hrs before or 12 Hrs after antacids, iron, vit/minerals.

Typical instructions and examples of when they apply,
from the Australian National Prescribing Service (NPS)
Instruction Examples ( brand names in brackets)
Take on an empty stomach Some antibiotics, such as erythromycin (Eryc) and flucloxacillin (Flopen, Floxapen, Staphylex), don't work as well if taken with food.

However, with some of these medicines, including erythromycin, if taking the medicine on an empty stomach causes stomach upsets, you can take it at a consistent time with respect to meals instead.

Don't take with certain foods Some antibiotics, such as tetracycline (Achromycin), and some osteoporosis medicines, such as alendronate (Fosamax), don't work as well when taken at the same time as calcium-rich foods, such as milk and yoghurt, and calcium supplements.
Don't eat certain foods at all Grapefruit juice interacts with several common medicines, making them work too strongly or causing unwanted side effects. People taking these medicines are advised not to eat grapefruit or drink grapefruit juice at all, because even one glass of juice can have an effect, and the interaction can occur even when the grapefruit or juice is eaten or drunk at a different time. Medicines that may interact with grapefruit and grapefruit juice include
  • some cholesterol-lowering medicines, such as atorvastatin (Lipitor) and simvastatin (Lipex, Zimstat, Zocor)
  • some heart and blood pressure medicines, such as amiodarone (Cordarone X) and felodipine (Felodur, Plendil)
  • cyclosporin (Cicloral, Cysporin, Neoral)
  • carbamazepine (Tegretol).
Other citrus juices like orange juice and lemon juice do not have the same effect.
Eat consistent amounts of certain foods Vitamin K interacts with the blood-thinning medicine warfarin (Coumadin, Marevan), and affects its ability to thin the blood. People taking warfarin should eat a consistent amount of vitamin K-rich foods each day (but not stop eating them -- they're good for you!), so the effect of the warfarin is consistent too. Vitamin K-rich foods include green vegetables, egg yolks, chickpeas and lentils.
Take with meals Many common arthritis medicines and painkillers, such as aspirin (Disprin), ibuprofen (Nurofen) and naproxen (Naprosyn), should be taken with meals to reduce the likelihood of developing stomach side effects, such as indigestion.
Source: Taking medicines with or without food: NPS (National Prescribing Service)
Foods To Avoid When Taking Antibiotics:
  • Dairy Products - Milk and other dairy products can aggravate your intestines while you're taking antibiotics. MedLine Plus particularly recommends against taking ciprofloxacin with milk, although taking it with foods that include milk as an ingredient should be okay.
    Avoid consuming all dairy, except yogurt, when you're taking antibiotics. According to the University of Iowa Hospitals and Clinics, the calcium content of dairy products can interfere with the absorption of the antibiotics. However, yogurt contains probiotics with active cultures that restore balance to your intestines if your antibiotics are causing diarrhea.
  • Fiber - Certain high-fiber vegetables and beans can also aggravate antibiotic-induced diarrhea. Wheat products fortified with iron or calcium can interfere with your body's ability to absorb some antibiotics, particularly quinolones, which include ciprofloxacin, nalidixic acid and cinoxacin, and a recently added group of flouroquinolones that include sparfloxacin and trovafloxacin.
  • Acidic Foods - The acid content in certain foods can disrupt your body's ability to absorb medications in general, according to an article in "The Chicago Tribune." You don't always have to avoid them entirely, however.
  • Alcohol - indicates that alcohol doesn't generally interfere with antibiotics. However, antibiotics and alcohol can have similar side effects, so consuming both together can increase the chance that you'll experience them. You might risk nausea, wooziness, dizziness or drowsiness.
  • All Foods - Many antibiotics do not interact well with any food at all. Generally, the insert with your prescription will advise you to take them on an empty stomach. These include penicillin G, ampicillin, floxin, oxacillin and ciprofloxacin. You can take tetracycline either 3 hours before you eat or 3 hours afterward.
Source: Foods To Avoid When Taking Antibiotics | LIVESTRONG.COM
How does grapefruit interact with medicines?
Eating grapefruit or drinking grapefruit juice affects how your body metabolizes (processes) certain medicines. The chemicals in grapefruit keep certain enzymes that normally process medicines from working correctly, which can cause higher levels of some medicines in your body. This makes it more likely that you will experience side effects from the medicine. Certain types of oranges, such as pomelo and seville, can also cause similar effects.

Interactions can happen up to 3 days after eating or drinking grapefruit. This means you cannot drink grapefruit juice in the morning and take your medicines later in the day to stop possible medicine interactions.
Source: Drug-Food Interactions: --

Dangerous Drugs and Products | Recall Report
Avoid Food-Drug Interactions (
Foods To Avoid When Taking Antibiotics | LIVESTRONG.COM
Drug-Food Interactions --
See also:
Drug Side Effects |
Drug Information, Side Effects and Interactions |
Information for Consumers (Drugs) > Side Effects: Questions and Answers |

last updated 25 June 2012