Interactions between drugs and foods refer to those unexpected, although not always adverse, effects that are produced by the joint taking of some drugs and foods. However, there may also be a negative interaction when the process of drug absorption is affected, which reduces its effectiveness and leads to treatment failure.
In addition, these interactions are also mutual; that is, there are drugs that can prevent the absorption of some nutrients from food . From the first descriptions of these interactions, dating from the twentieth century, to the present, we have been able to determine a little more than 300, of these there are very few clinically relevant.
Although the interaction is inevitable, many fail to significantly influence the effectiveness of the medication. Despite this, it is essential that professionals in health, pharmaceutical and nutrition are familiar with the subject to optimize the treatment of their patients and, in passing, ensure their nutritional status.
Types of drug-food interactions
The interactions between drugs and foods are classified taking into account which of the two undergoes a modification in their function due to the presence of the other.
- Food-drug interactions (AMI). They occur when the food, or any of its components, vary the bioavailability or pharmacokinetic or pharmacodynamic behavior of the medication.
- Drug-food interactions (IMA). The medicines interfere in the process of absorption of food, modifying its metabolic utilization and eliminating nutrients. They are also classified according to the mechanism that explains these interactions:
- Pharmacokinetics When the process of absorption, distribution, metabolization and excretion is modified or altered.
- Pharmacodynamics When it affects, it interferes with the mechanism of action of the medicines.
Drugs with more interactions
- Drugs with a narrow therapeutic margin , that is, those that must be ingested in exact doses, since the therapeutic dose is close to the toxic dose. Some examples are:
- Oral hypoglycemic.
- Oral contraceptives or lithium.
- Drugs that must maintain a sustained plasma concentration to be effective. For example, antibiotics.
- Drugs whose minimal changes in dose produce significant changes in the effect.
Foods that influence the effect of drugs
Foods that hinder the absorption of a drug
- Proteins They interfere in the absorption of L-DOPA, treatment of Parkinson’s disease. They are present in foods such as: meats, fish, dairy, pulses and eggs.
- Fats They reduce the effectiveness of drugs used in the treatment of AIDS (zidovudine, indinavir and didanosine) and, in addition, also reduce the action of .
- Dairy products. They affect the absorption and efficacy of medications such as antibiotics (tetracyclines) and oral penicillins. They also hinder the absorption of iron and laxatives that contain magnesium.
- Vitamin K. It tends to limit the absorption and efficacy of oral anticoagulants. It is found in: cabbage, beet, lettuce, spinach, peas, liver, .
Foods that block the action of a drug
- Licorice. It cancels the effects of antihypertensives, diuretics and beta-blockers. It is often used to improve the taste of: chewing gum, chocolates, beers, cigarettes.
- Tea. It affects the absorption of iron supplements due to its tannin content.
- Foods that enhance the action of a drug
- Garlic. Ingested regularly in the diet can potentiate the action of oral anticoagulants (warfarin and acenocoumarol), which increases the risk of
- Orange juice. It has a beneficial effect, because it increases the absorption of iron supplements that are prescribed for the treatment of anemia.
Foods that cause adverse effects
- Soy. It nullifies the effects of tamoxifen, an antiestrogenic action drug for the prevention of breast cancer. It causes toxicity when ingested with
- Grapefruit juice. It produces toxicity reactions when its consumption coincides with drugs for hypertension, antihistamines, hypocholesterolemic drugs and anti-rejection of transplants.
- Tyramine. It reacts negatively with antidepressants such as
Who is at greater risk of these interactions?
Although the interactions between drugs and food can occur in any person, there are population groups that, due to their condition, are more at risk and require more care:
- Pregnant women.
- Patients with renal failure.
- Patients with chronic diseases.
- People of low body weight.
- Elderly people (because the physiological changes of age affect the absorption, metabolism and elimination of the drug).
- Children (because their detoxification systems are still immature).
In conclusion, the interactions between food and drugs are multiple. In fact, they can cause beneficial and unwanted effects. As patients, it is essential to know the correct way to take the drug to obtain the desired effects and avoid adverse reactions.
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