Various foods can play a role, some positive and others negative, in how a drug functions during each stage. Absorption During absorption, a drug or food nutrient proceeds from the specific spot of administration, which is the gastrointestinal tract for food and most drugs, to systemic circulation. Changes in the rate of absorption and extent of absorption of a drug can be profound. Note that a specific drug-food interaction may affect the rate at which a drug is absorbed, but it may not affect the total amount of drug absorbed. This is an important issue because if the rate of absorption is too low, the drug may never reach its therapeutic levels.
Food can also increase the absorption of some drugs.
Some drugs offer a reduction in side effects when taken with food, which can reduce the gastrointestinal side effects of the drug without changing the efficacy. Once a drug is absorbed, it follows a distribution pattern based on several factors. If a drug is soluble in water, it will tend to be concentrated in the water-soluble compartments of the body like the bloodstream. Some drugs will bind to the circulating protein within the blood, making very little drug available for tissue penetration. In hypoalbuminemia, where the amount of circulating proteins is reduced, the amount of a protein-bound drug is decreased, thereby increasing the effect of a given dose of that drug.