Author: Dr Santhosh R, MBBS, MD, Professor, Department of Pharmacology, BGS Medical College & Hospital.
It is of paramount importance to both treating doctor and the patient that the prescribed drugs are both safe and effective. One of the important yet often neglected facts about drug interaction is food- drug interaction.
A food drug interaction is said to have occurred if food consumed along with the medication affects its effectiveness or safety profile or both which would have not occurred in the absence of food.
Disclaimer: This guide gives an overview of interactions of your medicines with food, caffeine and alcohol. It should never replace nor serve as a guide to oppose your doctor’s advice. Always listen to your treating physician.
It can be generalized that most of the foods will interact with the drug when consumed simultaneously but it is important to note that not all interactions cause significant effect to the health of the patient or final outcome of the therapy. It is therefore pertinent to have awareness about those food drug interactions that are important and that can affect the overall health and therapy success.
Food interacting with a drug can either cause
1.Decrease in the effect,
2.Increase in the effect,
3.Complete absence of effect or
4.It can bring a new effect to a drug.
All these are unfavorable and undesirable for the final outcome of the success of therapy of a particular disease. These effects will further increase the cost of therapy and the discomfort to the patient.
Food drug interactions may not affect everyone in the same way. Seriousness of outcome depends on several factors like
1.Age of the patients wherein children and elderly are more seriously affected,
2.General health of the patient wherein if the patient is very ill due to any reasons like having disorders of kidney, liver or heart then food drug interaction can be more serious among such individuals
3.Patient is taking multiple drugs from multiple doctors at the same time for a same or different conditions
4.Patients taking drugs from different systems of medicine. Eg: combining ayurvedic and allopathy drugs together.
Interaction of food with drug can alter its absorption from the body, its distribution within the body, its metabolism in the body or finally its excretion. Food drug interactions can also affect the effectiveness of the drug.
It is also important to know that certain foods are to be consumed on an empty stomach like proton pump inhibitors used in gastritis (pantoprazole, lansoprazole or rabeprazole), thyroxine used in hypothyroidism etc. and certain drugs after food.
Here are some of the examples of food drug interactions that can significantly affect the action of the drug and or cause side effects to the patient
Medicines used for allergy, cold, cough or sneezing
Eg: Cetirizine, Levocetirizine, Chlorpheniramine, Desloratadine, Diphenhydramine, Fexofenadine etc.
Consumption of alcohol along with these medicines can increase drowsiness caused by these medicines. Do not operate any heavy machinery nor drive vehicle if these drugs are consumed.
Medicines given for fever
Eg: Paracetamol
Paracetamol itself can damage the liver on long term or high dose consumption and consumption of alcohol along with paracetamol further increases potential for liver damage.
Medicines given for pain, arthritis and inflammation
Eg: Aspirin, Celecoxib, Diclofenac, Ibuprofen, Ketoprofen, Naproxen etc.
These drugs can irritate the stomach and can cause gastritis hence these drugs have to be consumed only after a substantial meal. Consumption of milk also helps in decreasing the gastritis caused by these drugs. Heavy and chronic drinkers should be careful in consuming these drugs since it can lead to stomach bleeding.
Medicines used for bronchial asthma or chronic bronchitis or emphysema
Eg: Albuterol/Salbutamol, Theophylline
These drugs are used for dilating the bronchi to ease the breathlessness, consumption of these drugs with foods/beverages containing caffeine like tea, coffee or energy drinks can cause rapid heartbeat, excitability and nervousness.
Consumption of alcohol along with theophylline can cause nausea, vomiting, headache, and irritability.
Medicines used for increased blood pressure/hypertension
Eg: ACE inhibitors/ARB like Captopril, Lisinopril, Losartan, Candesartan etc. and diuretics like triamterene and spironolactone.
These drugs tend to increase potassium levels and consumption of food rich in potassium like bananas, oranges, green leafy vegetables, and salt substitutes that contain potassium can lead to severe increase in potassium levels and cause several cardiac side effects like irregular heartbeats etc.
Medicines used in heart failure
Eg: Digoxin
Avoid taking fiber rich foods along with digoxin since it decreases its absorption. Ideally digoxin should be taken on hour before food or 2 hours after food. Avoid consuming licorice (contains glycyrrhizin used in making cakes and candies) along with digoxin since it may lead to irregular heartbeat.
Medicines used in hypercholesterolemia
Eg: Statins like Atorvastatin, Fluvastatin, Lovastatin, Pravastatin, Simvastatin, Rosuvastatin etc.
Statins are best taken after dinner for better lipid lowering effect. Do not consume grape juice along with statins since it can increase the blood levels of some statins and cause increase in side effects. This does not apply to all statins and hence consult your doctor about your prescribed drug. Avoid alcohol since it increase the chance of liver damage.
Medicines used for chest pain (angina pectoris)
Eg: Isosorbide Dinitrate or Mononitrate, Nitroglycerin etc.
These drugs dilate your blood vessels and cause lowering of blood pressure. Consumption of alcohol along with them can cause dangerous drop in blood pressure
Medicines used to prevent clot formation/ Blood Thinners
Eg: Anticoagulants like warfarin
Presence of vitamin K in your food lowers the effect of these drugs hence it should be avoided. Vitamin K rich foods are broccoli, cabbage, collard greens, spinach, kale, turnip greens, and brussel sprouts. Avoid cranberry juice since it is known to change the effects of warfarin. Also avoid garlic, ginger, glucosamine, ginseng, and ginkgo because they can increase the chance of bleeding.
Medicines used in gastritis, reflux disease and peptic ulcers (stomach and duodenal ulcers)
Eg: Proton Pump Inhibitors like Dexlansoprazole, Esomeprazole, Lansoprazole, Omeprazole, Pantoprazole, Rabeprazole etc.
For optimum benefit from these drugs it is advisable to take these drugs on en empty stomach with just a sip of water.
Medicines used for hypothyroidism
Eg: Levothyroxine
Levothyroxine should be taken on empty stomach early in the morning atleast 1-2 hours before breakfast. Avoid taking foods containing soybean, cotton seed meal, walnuts and dietary fibre. If so inform your doctor since dose change might be necessary.
Medicines used for bacterial infections
a. Fluoroquinolones like Ciprofloxacin, Levofloxacin, and Moxifloxacin.
Tablets of these drugs can be taken on full or empty stomach but levofloxacin oral solution should be taken one hour before food or two hours after food. Don’t take ciprofloxacin with dairy products (like milk and yogurt) or calcium-fortified juices alone, but you can take ciprofloxacin with a meal that has these products in it. Avoid caffeine intake with these drugs.
b. Tetracycline like Doxycycline, Minocycline and tetracycline.
Take these medicines one hour before a meal or two hours after a meal, with a full glass of water. You can take tetracycline with food if it upsets your stomach, but avoid dairy products (such as milk, cheese, yogurt, ice cream) one hour before or two hours after.
c. Linezolid
Avoid tyramine containing foods along with linezolid since it can cause dangerous increase in blood pressure. Tyramine containing foods are caffeine, alcohol, processed cheese, beef, chicken, sausages, avocados, bananas, canned figs, dried fruits (raisins, prunes), raspberries, overripe fruit, sauerkraut, soy beans and soy sauce, yeast extract and excess amounts of chocolate.
d. Metronidazole
Avoid drinking alcohol while taking metronidazole and for at least one full day after finishing the medicine; together alcohol and metronidazole can cause nausea, stomach cramps, vomiting, flushing, and headaches.
Medicines used for fungal infections
Eg: Fluconazole, Itraconazole, Posaconazole, Voriconazole, Griseofulvin, Terbinafine etc.
Tablets of Itraconazole and Posaconazole should be ideally taken after full meals. Itraconazole solution should be taken on empty stomach. Griseofulvin should be taken after full fatty meals for maximizing beneficial effects. Griseofulvin taken along with alcohol makes the effects of alcohol worse like nausea, stomach cramps, vomiting, flushing, and headaches.
Medicines used for treatment of tuberculosis
Eg: Ethambutol, Isoniazid, Rifampin, Rifampin + Isoniazid, Rifampin + Isoniazid + Pyrazinamide
Isoniazid should not be taken with foods containing tyramine since it can lead to dangerous increase in blood pressure and one should avoid taking isoniazid with foods containing histamine since it can lead to headache, sweating, palpitations (rapid heartbeats), flushing, and hypotension. Foods with histamine include skipjack, tuna, and other tropical fish. Avoid alcohol since these drugs along with alcohol can severe damage liver function of the patient.
Medicines used for anxiety and panic disorders
Eg: Alprazolam, Clonazepam, Diazepam, Lorazepam etc.
Avoid alcohol along with these drugs since alcohol can exaggerate sedation and depressant functions of these drugs on the brain.
Medicines used for depression
Eg: MAO Inhibitors like Phenelzine, Tranylcypromine etc.
Avoid alcohol, caffeine and tyramine containing foods.
Medicines used for psychosis
Eg: Aripiprazole, Clozapine, Olanzapine, Quetiapine, Risperidone, Ziprasidone etc.
Ziprasidone should be taken with food; rest of the drugs can be taken with empty or full meals. Avoid taking caffeine with clozapine since it can increase its blood levels and side effects. Avoid alcohol since it can increase the side effects like sedation.
Medicines used for insomnia
Eg: Eszopiclone, Zolpidem etc.
To get to sleep faster, don’t take these medicines with a meal or right after a meal rather take these drugs on empty stomach before dinner. Avoid alcohol since consumption of alcohol will exaggerate side effects of these drugs.
Medicines used for bipolar disorders and mania.
Eg: Carbamazepine, Divalproex Sodium, Lamotrigine, Lithium etc.
Divalproex Sodium can be taken with food if stomach upset happens if taken on empty stomach. Lithium should be taken after full meals. Lithium can cause loss of sodium from the body hence it is advisable to be well hydrated and maintain normal diet with adequate salt intake.
Medicines used for osteoporosis
Eg: Alendronate Sodium, Alendronate Sodium + Cholecalciferol, Ibandronate Sodium, Risedronate Sodium, Risedronate Sodium + Calcium Carbonate etc.
These medicines work only when you take them on an empty stomach. Take the medicine first thing in the morning with a full glass (six to eight ounces) of plain water while you are sitting or standing up. Do not consume antacids, mineral water or foods rich in vitamins and calcium atleast 30-60 minutes after taking these drugs. Avoid lying down atleast for 30-60 min after taking these drugs.
