It is the interaction between a medicine taken by a human with another medicine, food, drink or supplement at the same time, and it may cause loss of effectiveness of the medicine or increase the toxicity or emersion of undesirable side effects that do not occur when taking the medicine alone.


Drug interactions with food and drink may delay or stimulate the absorption of the drug from the intestine. Sometimes the metabolic rates of the drug and the removal of the metabolic products from the body are also affected by the intake of certain foods.  So that experts recommend taking some drugs on an empty stomach (an hour before or two hours after eating). Some medicines are easier to tolerate when taken with food. Such as aspirin and non- steroidal analgesics, so be sure to ask your doctor or your pharmacist whether it’s okay to take your medicine with a snack or a meal or whether it should be taken on an empty stomach.

 Among the most popular foods and beverages that can interact with medicines:


It reduces the effectiveness of diuretics and antihypertensive drugs, and increases the effectiveness of certain steroids, causing undesirable side effects.


 It contains the tannin which inhibits the absorption of the non- heam iron (originating from the plant food) in the intestine and thereby limits the benefit of it.

Green Leafy Vegetables:

Eating too much green leafy vegetables (especially spinach), which are high in vitamin K, can decrease the ability of blood-thinners to prevent clotting.

Milk and dairy products:

It reduces the absorption of antihypertensive drugs and antibiotics due to its richness in calcium carbonate.

Cheese, chocolate and smoked meat:

Its high content of the amino acid (tiramine) causes a sudden and dangerous rise in blood pressure when combined with antidepressants.

Grapefruit juice:

Grapefruit juice has the ability to interact with medications in various ways. One way is by increasing the absorption of certain drugs as is the case with some, but not all, cholesterol-lowering statins.

Grapefruit juice can also cause the body to metabolize drugs abnormally, resulting in lower or higher than normal blood levels of the drug. Many medications are affected in this way, including blood pressure drugs (calcium channel blockers).

Fiber-rich foods:

It decreases the effectiveness of some medicines because they combines with  some substances in it,  such as metformin, which regulates blood sugar, and digoxin  which is used to treat heart disease and levothyroxine to treat thyroid diseases.

Vitamin B12:

Some medications such as omeprazole and lansoprazole reduce stomach absorption of vitamin B12, which can negatively affect its body levels.

Facts to remember about drug-food interactions

  • Read the prescription label on the container. If you don’t understand something, ask your doctor or pharmacist.
  • Read all directions, warnings and interaction precautions printed on medicine labels and packages. Even over-the-counter medicines can cause problems.
  • Take medicine with a full glass of water, unless your doctor tells you differently.
  • Don’t stir medicine into your food or take capsules apart (unless your doctor tells you to) because this may change the way the drug works.
  • Don’t take vitamin pills at the same time you take medicine because vitamins and minerals can cause problems if taken with some drugs.
  • Don’t mix medicine into hot drinks because the heat may keep the drug from working.
  • Never take medicine with alcoholic drinks.