Background of the issue

The effect of fruit juice on the effects of drugs in the human body was discovered almost by accident in the late 1980s: Canadian researchers investigated the interaction of alcohol with blood pressure medications and used grapefruit juice to mask the taste of alcohol. It turned out that grapefruit leads to a multiple increase in the effect of medications. This launched a wave of research that continues today. Scientists have described the mechanisms of the effect of grapefruit on the medicinal effect of various drugs and compiled lists of drugs that interact with this citrus. And, of course, we tested many other fruits, berries and juices made from them for interaction with medicines. The results of their research migrated to the drug instructions in the form of warnings not to drink juice or eat fruit while taking the medication — but not all, so it’s useful to list and explain which fruits and juices can be harmful when interacting with pills.

Grapefruit

The most studied fruit that produces the most severe side effects. It’s all about the substances contained in grapefruit juice — furanocoumarins. As it turned out, they deactivate enzymes that act in the intestines and liver — cytochromes, which is especially responsible for breaking down a large number of drugs cytochrome CYP3A4. In a normal situation, the work of this enzyme leads to the fact that not the entire volume of the active substance from the swallowed tablet enters the bloodstream, and the drugs are produced with the expectation of this natural decrease in concentration. If you drink a glass of grapefruit juice with the pill or even many hours before it, it will block the enzyme from working — and you will receive a significantly increased dose of the drug, sometimes several times! CYP3A4 is involved in the metabolism of almost half of existing drugs; overdose and side effects from grapefruit have been proven for at least 85 different tablets, for example:

arrhythmia drugs: amiodarone, dronedarone, quinidine;

statins that regulate cholesterol levels: atorvastatin, lovastatin, simvastatin;

drugs for reducing blood pressure: felodipine, nifedipine;

heart drugs: clopidogrel, ticagrelor;

anticoagulants: apixaban, rivaroxaban;

immunosuppressive drugs: cyclosporine, everolimus, tacrolimus, sirolimus;

antipsychotic drugs, neuroleptics: pimozide, quetiapine, lurasidone, ziprasidone; anti-anxiety drugs (buspirone) and tranquilizers (triazolam);

anticancer drugs: crizotinib, erlotinib, everolimus, lapatinib and others.

There is evidence that grapefruit can also act on medications taken in the opposite way: reduce their concentration in the blood and make therapy ineffective. In this case, the problem is to block transporters, peptides and proteins that carry active substances. Such an interaction was found with fexofenadine, an antiallergic drug. It is assumed that it is not furanocoumarins that are to blame for reducing the dose of drugs, but flavonoids, in particular naringenin, another active substance in grapefruit.

Other citrus fruits

Other citrus fruits can affect the absorption of drugs in the same way as grapefruit — through metabolizing enzymes or through transporters, but the data on them are less detailed and more contradictory. The main thing that can be said is that there are no described cases of severe side effects for them.

Orange juice does not contain furanocoumarins or naringenin (its main flavonoid is hesperidin), so it does not have as strong effects as grapefruit juice. However, in a study on volunteers with the already mentioned allergy drug fexofenadine, orange juice also reduced the drug’s concentration in the blood. Another scientific work found that it reduces the absorption of alendronate, a drug for osteoporosis, by more than half. This is important because alendronate already has a rather poor bioavailability — and when used with orange juice, the drug can become completely ineffective.

Pomelo, Seville orange and lemon juices were tested for interaction with sildenafil, a drug for erectile dysfunction. Seville orange increased the concentration of the drug, but no side effects were observed. Lemon did not show any interaction, and pomelo, a fruit related to grapefruit, lowered the dose of the drug in the blood.

Apple

Apple juice can also interact with medications taken. For example, it, like grapefruit and orange juices, reduces the effectiveness of the antihistamine fexofenadine. Other drugs whose concentration it affects are pressure pills (atenolol, aliskiren) and the antiasthmatic and anti-allergic drug montelukast. This may be due both to the suppression of the functioning of transport substances and to an increase in acidity in the gastrointestinal tract, since the experiments used a large amount of apple juice. In any case, drinking apples and apple juice mainly threatens to weaken the performance of drugs, and not with significant side effects.

Banana

Bananas, as well as avocados, dried apricots and prunes, and grapefruit are rich in potassium, an important mineral that is essential in many physiological processes, such as regulating blood pressure, heart rate, and the amount of fluid in tissues. However, this additional potassium from fruits can lead to side effects when taking pressure medications from the group of ACE inhibitors, angiotensin-converting enzyme (ramipril, captopril, moexipril), which are potassium-sparing. This combination creates an excess of potassium, hyperkalemia, which is fraught with heart rhythm disorders, including a threat to life. The same effect can occur when these fruits and dried fruits are combined with spironolactone and triamterene diuretics.

The bright side

By affecting the behavior of drugs in the body, fruits and fruit juices do not always create obstacles and dangers; interactions can benefit treatment. Here are a few examples.

The fact that grapefruit juice increases the digestibility of the immunosuppressive agent cyclosporine makes it possible to prescribe a reduced dose of the drug, which reduces its side effects and helps patients better tolerate therapy. Another example is taking lime juice together with a malaria drug. In a study on children, juice accelerated the elimination of the parasite and probably prevented resistance to therapy. Freshly squeezed blueberry juice worked in a similar way on children who were treated with etanercept for juvenile idiomatic arthritis: the symptoms went away, while reducing the side effects of the drug.

Orange juice increases iron absorption, and this effect can be a big plus in the treatment of iron deficiency anemia, which is common in children and adults.

Source: https://food.ru/

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