When we think of interactions between medications, it is mostly drug-drug interactions that we take into consideration. Food interactions with medication are also a possibility.  Major effects of diet include alteration in absorption by fatty, high protein, and fiber diets.  These alterations in absorption of medications may be associated treatment failure due to reduced bioavailability when one has a full stomach. A common example is foods that contain vitamin K , such as broccoli, kale, and spinach, all of which  have interaction with warfarin. The pharmacokinetic and pharmacodynamics profiles of many other medications may be altered by diet. Cranberry juice may cause an elevated INR.

Grapefruit juice possesses high interaction potential to many medications including but not limited to psychotropic, anticonvulsants, and cholesterol lowering agents.  Consumption of grapefruit juice with anticonvulsant or psychotropic should be limited or avoided as contraindications may exist. Lovastatin should be taken with food to enhance absorption and bioavailability.  The absorption and efficacy of antihypertensives such as beta-blockers and ACE inhibitors may be altered by diet. Carvedilol should be taken with food to limit potential of hypotension. Propranolol serum levels may have the potential to increase if taken with protein rich food. ACE inhibitors can increase potassium levels. High potassium may cause irregular heart rhythms, thus importance of limiting potassium content in diet.

Tyramine containing foods are recommended to be limited with a couple different medications. Tyramine is an amino acid that helps regulations blood pressure.  Monoamine oxidase inhibitors (MAOIs) can be used to treat depression and those on these drugs should avoid tyramine rich foods, such as, but not limited to aged cheese, salami, meat extracts, and dried fruits (raisins, prunes).   To avoid sudden and dangerous increase in blood pressure, patients that are on these medications that inhibit monoamine oxidase should limit tyramine containing foods.  It is often hard to consider impact of diet on medications as our diet changes daily. Diet restrictions with certain medications may play a role in the overall efficacy and safety. The administration of a medication on an empty stomach or with food is an important factor to consider and on which to educate patients.