▪️ Food and drugs are essential components of the patient’s therapeutic plan. Like drugs, food has increasingly become a key element in the prevention and treatment of diseases . However, the interaction between them is one of the main challenges, especially for oral medications.

The interaction between food and drugs could lead to treatment failure or predispose the patients for many side effects that could be life-threatening.

▪️ Mechanism of drug food interaction:

The interaction can be classified by two categories: pharmacokinetic and pharmacodynemic interaction .

▪️the most common pharmacokinetic interaction 

☆Drug Absorption Interaction:

Food can increase or decrease  drug absorption in the GI tract by altering gastric pH, secretion, gastrointestinal motility ,  transit time, damageto the bacterial flora, and the formation of indigestible complexes  

(Ex, Mineral-rich foods such as: Fe, Ca, Mg, Al, Zn form insoluble complexes with these drugs: tetracyclines, quinolones, penicillamines, and thus greatly inhibit their absorption )

☆Drug metabolism interaction:

different foods affect liver enzymes, namely Cytochrome P450 by inhibiting/stimulating these enzymes, thereby reducing/increasing the biotransformation of drugs. Reduction of  biotransformation of drugs results in a higher concentration of the drug in the blood which can lead to toxicity, while induction of hepatic enzymes leads to faster biotransformation of the drug resulting in decreased concentration below therapeutic values failing therapy.

(Ex,Grapefruit inhibits CP450 and  can cause toxicity of some drugs: carbamazepine, benzodiazepines, ivabradine, terfenadine, sertaline, and fluvoxamine )

▪︎pharmacodynemic interaction:

Interactions between drugs and food can also affect the pharmacodynemic of drugs, resulting in synergism or antagonism of the effect of the drug, or the presentation of a new effect of this combination, which is often a toxic condition

(Ex ACE-inhibitors  with food rich in potassium like banana cause hyperkalemia )

(Warfarin with food rich in vitamins K cause Antagonistic effect)

Source 

Choi, J. H., & Ko, C. M. (2017). Food and Drug Interactions. Journal of lifestyle medicine