To drink or not to drink: What can not be combined drugs
In certain situations, medications have to take every person. It seems that the basic rules are well known to everyone: do not combine antibiotics with alcohol or, for example, do not drink tablets on an empty stomach, so as not to harm the stomach. But how justified are these rules and how to make the treatment as effective and safe as possible? We understand which medications are incompatible with each other, whether it is possible to take two tablets in the evening, if you are prescribed one twice a day, and what does the grapefruit have to do with it.
Olga Lukinskaya
Why grapefruit juice may be incompatible with treatment
The metabolism of many drugs (that is, their transformation into molecules that are easily removed from the body) occurs in the liver, and the enzymes of the so-called cytochrome system, among others, are responsible for this. There are drugs and products that enhance or reduce the activity of these enzymes or "compete" for them with the medication taken. All this can affect what happens to the drug in the body. First of all, this refers to opioids, immunosuppressants, antitumor drugs, and from more common ones - to drugs for treating arterial hypertension and statins, which reduce the levels of lipids in the blood.
If the activity of the enzymes that process the medicine is reduced, then the concentration of the drug in the blood will be higher than necessary — which means that all effects, including undesirable ones, may increase. This is especially dangerous in the case of, for example, immunosuppressants. Cytochrome enzyme inhibitors include the antifungal agents ketoconazole and itraconazole, the antibiotic clarithromycin, and also grapefruit, carambola (star fruit), aloe juice, and some other products. The interaction of drugs with grapefruit derivatives is best studied - this fruit in any form is incompatible with almost a hundred drugs. Red oranges, limes and pomelo can have the same effect (increased drug activity and risk of side effects).
Interestingly, sometimes cytochrome enzyme inhibitors are used deliberately to achieve the desired concentration of the drug when taking a lower dose. One of the groups of drugs for the treatment of HIV infection (HIV protease inhibitors) is now used in the form of so-called "boosted", or enhanced ritonavir (a substance that suppresses the very cytochrome enzymes in the liver). For example, instead of 1000 mg of the drug in its pure form, 400 mg of the active substance and 100 mg of ritonavir are sufficient for the same effect. Given the cost of treating HIV infection, it helps make it more accessible.
What does the herbal tea
Traditional medicine is not nearly as harmless as it seems - including because the components of herbs and roots are able to interact with ordinary medicines in unexpected ways. Strong raspberry leaf tea can have the same effect as grapefruit juice; this applies to the Chinese lemongrass, and the Canadian yellow root (the popular dietary supplement "from all diseases"). Black pepper will not affect the metabolism of drugs, if used as a seasoning, but can harm in a large dose (again, as part of dietary supplements).
Other herbal remedies - for example, St. John's wort and echinacea - on the contrary, stimulate cytochrome enzymes, increasing their activity. The drug is metabolized faster than necessary, and does not have the desired effect. If it happens chronically (for example, a person takes a dietary supplement every day), then the treatment will simply be ineffective, and the disease will progress.
What about alcohol
There are legends about the incompatibility of alcohol - many people think that even a drop of champagne will cause irreparable harm. In fact, antibiotics are a large class of drugs, and alcohol is banned only for some of them. So, drinking in combination with taking metronidazole can lead to headache, nausea and vomiting (although large doses of alcohol are capable of these effects without antibiotics). Linezolid taken with wine or beer can cause a dangerous increase in blood pressure. And of course, it must be remembered that both drugs and alcohol cause the liver to work more actively - and it is better not to overload the valuable organ.
But NSAIDs (paracetamol or ibuprofen) taken for any pain can actually harm the liver, and it is better not to combine alcohol with them or reduce its amount to a minimum. The article in 2016 states that out of 2,000 cases of liver toxicity per year, the reason was to take drugs in more than half of the cases, and in 39%, specifically paracetamol. In general, it is believed that small doses of alcohol with the correct doses of medication are safe - provided that a person does not have liver disease.
Is it possible to catch up with the missed dose
If it is recommended to take the medicine twice a day, this means that the interval between doses should be about twelve hours - and for three times a day, respectively, about eight. Of course, it is more convenient and easier to take one dose per day, as there is less risk of forgetting to take the medicine, especially during the day when the person is away from home. But if the drug is prescribed with such frequency (more than once a day), there are reasons for this. They are related to the fact that the drug is processed and excreted from the body in a certain time, independently or almost independently of the concentration.
If the pill lasts only eight hours, then two pills taken at the same time will be enough for these eight hours - but the concentration in the blood may be too high. If you missed taking a serious medication, study the instructions again - usually it says there, at what time interval you can take the missed pill, and when you can’t. Particularly difficult is the scheme for oral contraceptives: skipping the pill on one day of the cycle does not reduce the effectiveness, while on others it requires the use of condoms for several days.
Can I take medicine on an empty stomach?
For some drugs, taking it on an empty stomach is a must, because food can interfere with their absorption. It happens that food components (for example, iron or calcium) bind to drug molecules, inactivating them - so, for example, drugs for osteoporosis need to be taken on an empty stomach. There are drugs, the effectiveness and safety of which does not change regardless of the meal, so they can be taken at any convenient time.
In clinical studies, they study the administration of drugs not only on an empty stomach or after meals, but also in more specific conditions - for example, with fatty foods or light snacks. This is done in order to make the study group more homogeneous, and in search of the possibility of reducing the dose without losing effectiveness. So, there is evidence that foods high in fat may significantly enhance the effect of lapatinib, a drug for treating breast cancer. However, while in the instructions for most drugs it is hardly possible to meet more specific instructions than “take on an empty stomach” or “take after a meal.”
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