Some Interesting Drug and Food Interaction Causing Toxicity

It is a well-known fact that drugs can cure diseases and improve our health. But many times, you don’t get the exact results from the drug as expected. This happens because your medicine interacts with foods, beverages, and every supplement you consume while taking this medication. 

The medicines you take have powerful ingredients which can interact with your body differently. Your diet and lifestyle can have a huge impact on drugs and their functions.

When we say drug interactions, we typically think its drug-drug interactions. However, interaction can happen between drugs and foods (drug-food interaction) and drugs and herbs (drug- herb interaction). A drug-food interaction occurs when certain foods interact with medications. These interactions can happen with both over-the-counter medicines and prescribed drugs. 

Drugs work efficiently only when taken in the appropriate quantity with the right combination of drugs and foods and at an appropriate time. Though drug-food interactions are complex and difficult to determine, few common interactions can be avoided. Let us discuss some of these interactions and how you can prevent them. 

Common Drug and Food Interactions

Here is the list of common food-drug interactions and how you can avoid them: 

Fruit Juices

Among many fruits, grapefruit juice has a high interaction rate with most of the drugs. It can modify the metabolism of the medicines, and it can also affect your liver’s ability to metabolize the drug. Most of the drugs get metabolized in your body with the help of the enzyme CYP3A4. 

Studies suggest that furanocoumarins present in grape juice inhibit CYP3A enzymes, due to which the drugs are not metabolized, and the drug stays in the blood for a very long time.

CYP3A and other enzymes can break down some drugs, such as statins that are used to lower cholesterol. When you take fruit juices with such medicines, either they block the action of these enzymes or increase the content of the drugs in your body, which may lead to several other side effects. 

You can check the label when you are taking any drug, as some medications recommend avoiding taking fruit juices along with it. 

Diary Products 

Your doctor might have prescribed you antibiotics several times. But do you know certain antibiotics should not be taken with milk?

Various dairy products like milk, cheese, yogurt can delay the absorption of antibiotics, such as tetracyclines and ciprofloxacin. The calcium present in dairy products binds to the antibiotics in the stomach and forms an insoluble compound. 

Studies suggest that drugs such as fluoroquinolones and tetracyclines bind to calcium in milk. This results in decreased drug absorption and potential therapeutic failure.  

Although dairy products are safe, they don’t go well with some antibiotics. Hence avoid dairy products while taking antibiotics. 

Green and Leafy Vegetables

Leafy and green vegetables are rich in vitamin K. They react with the drugs such as aspirin which cause thinning of the blood. They also interfere with the effectiveness of warfarin drugs. 

If you’re on blood thinner drugs such as jantoven, coumadin; you may have to regulate your intake of green leafy vegetables. These drugs regulate blood flow in the liver. Vitamin K is essential for the formation of blood clots. These drugs reduce the formation of blood clots by blocking vitamin K synthesis and allow easy flow of blood.

Green leaves are rich in vitamin K and are healthy; you don’t have to stop eating them. You can consider eating green leaves such as spinach, collard greens, and turnip greens once or twice a week. 

Caffeinated Drinks

If you are a regular coffee person, then be cautious when you are on stimulant drugs. Caffeine can react with stimulant medications and causes serious problems, including increased heart rate and high blood pressure. 

You must avoid taking caffeine along with drugs such as diethylpropion, epinephrine, phentermine, pseudoephedrine, and many other stimulant drugs.

Several studies suggest that extensive consumption of coffee when you are on stimulant drugs may affect the metabolism, distribution, absorption, and excretion of these drugs.

Caffeine can affect the therapeutic functions of the drug and can even cause toxic reactions. 

It is advised to have an appropriate time gap between intake of drugs and caffeine. Discuss with your healthcare provider or pharmacists if you have any concerns about potential drug interactions with coffee.


If you are diabetic, then alcohol consumption can interfere with your diabetic medications. Alcohol prolongs the effects of insulin and diabetic drugs resulting in low blood sugar. This action might last for 8 to 12 hours. Common symptoms observed due to the drug and alcohol interactions include nervousness, sweating, trembling, intense hunger, confusion, drowsiness, and sometimes coma. 

Discuss with your doctor regarding your alcohol intake and diabetic drugs. Your doctor may suggest moderate alcohol consumption only if you don’t have any secondary health problems such as pancreatitis, increased triglycerides, and neuropathy. You can reduce the risk of low blood sugar by taking drinks during mealtime or during snack time.  According to the American Diabetes Association, one serving of drink is 12 ounces of beer, 1.5 ounces of whiskey, vodka, or gin, and 5 ounces of wine.  

If you have any concerns, talk to your doctor and follow your healthcare provider’s advice. Generally, alcohol is not recommended when you are on any medication. 

Iodine Rich Foods

Antithyroid drugs are used to treat hyperthyroidism. They block the production of thyroid hormones and thus reduces hyperthyroidism. 

Antithyroid drugs prevent iodine absorption in the stomach to reduce the production of thyroid hormones. During this time, if you consume a high-iodine diet, it can counteract the effects of antithyroid drugs. Also, you may require high doses of these drugs, which may lead to side effects such as rashes, hives, and liver diseases.

You should avoid the high-iodine foods such as seed weed, seafood, and iodized salt in your diet when you are on antithyroid drugs. 

Here is the list of common drug-food interactions:

DrugsFood that interactsEffects
Warfarin High-protein diet  Green leaves rich in vitamin KInterferes with the effectiveness and safety of warfarin therapy.
Antibiotics Diary products Calcium ions complex with some antibiotics and prevent their absorption. Reduces drug bioavailability
Monoamine oxidases drugs or antidepressantsTyramine-containing foodHypertensive crisis
Asthma drugs such as theophyllineHigh-fat meals Increases bioavailability
Ca2 channel blockers drugs  (calcium channel blockers)Grape juice Increases bioavailability 

Final Words 

Drug-food interaction can result in various adverse effects and pose threat to the safety and efficiency of a drug. Though it is essential to be aware of drug-food interactions, discussing your medications with your health care provider is equally important. Always check the labels of your medicines to use them effectively. Generally, any food present in your digestive tract can affect the drugs you take. Hence it is recommended to take medications one or two hours after eating.