IN THESE OR OTHER SITUATIONS, DRUGS have to be taken by every person. It seems that the basic rules are known to everyone: do not combine antibiotics with alcohol or, for example, do not drink pills on an empty stomach, so as not to harm the stomach. But to what extent are these rules justified and how to make the treatment as effective and safe as possible? We figure out which medications are incompatible with each other, is it possible to take two tablets in the evening, if one is prescribed twice a day, and what does grapefruit have to do with it.
Why grapefruit juice may be incompatible with treatment
The metabolism of many drugs (that is, their transformation into molecules that are easily excreted from the body) occurs in the liver, and enzymes of the so-called cytochrome system are responsible for this, among others. There are drugs and foods that increase or decrease 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 applies to opioids, immunosuppressants, anticancer drugs, and from the more common – to drugs for the treatment of arterial hypertension and statins, which lower blood lipid levels.
If the activity of enzymes that process the drug is lowered, 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, 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 (increasing the activity of the drug and the risk of side effects).
Interestingly, sometimes cytochrome enzyme inhibitors are used deliberately to achieve the desired drug concentration at 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 the so-called ” boosted ” or reinforced with ritonavir (a substance that suppresses the very enzymes of cytochrome 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 HIV treatment, this helps make it more affordable.
What does herbal tea have to do with it?
Means of traditional medicine is not as harmless as it seems – including the fact that the components of herbs and roots are capable of the most unexpected way to interact with conventional drugs. Strong tea made from raspberry leaves can have the same effect as grapefruit juice; this applies to both Chinese magnolia vine and Canadian yellow root (a popular dietary supplement “for all diseases”). Black pepper will not affect the metabolism of drugs if used as a seasoning, but it can do much harm in a large dose (again, as part of a dietary supplement).
Other herbal remedies, such as 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 this 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 – it seems to many that even a drop of champagne will cause irreparable harm. In fact, antibiotics are a large class of drugs, and only a few of them are banned from alcohol. So, drinking in combination with taking metronidazole can lead to headaches, nausea and vomiting (although large doses of alcohol are capable of these effects without antibiotics). Linezolid taken with wine or beer can cause dangerous high blood pressure. And of course, you need to remember that both drugs and alcohol make the liver work more actively – and it is better not to overload the valuable organ.
But NSAIDs (paracetamol or ibuprofen) taken for any pain can really harm the liver, and it is with them that it is better not to combine alcohol or reduce its amount to a minimum. In a 2016 article, it is said that out of 2,000 cases of liver toxicity per year, the reason was the use of drugs in more than half of the cases, and in 39% – specifically paracetamol. In general, small doses of alcohol with the correct dosage of medication are believed to be safe – provided that the person does not have liver disease.
Can I catch up with the missed dose?
If the medicine is recommended to be taken 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, taking one dose per day is more convenient and easier, as there is less risk of forgetting to take the medicine, especially during the day when a person is out of the house. But if the drug is prescribed precisely with this frequency (more than once a day), there are reasons for this. They are associated with the fact that the drug is processed and excreted from the body for a certain time, independently or almost independently of the concentration.
If the pill is only enough for 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, read the instructions again – usually it says in what interval of time you can take the missed pill, and when you can not do it. The scheme for oral contraceptives is especially complicated: skipping a pill on some days of the cycle does not reduce the effectiveness, while on others it requires the use of condoms for several days.
Can I take medication on an empty stomach?
Some drugs must be taken on an empty stomach because food can interfere with absorption. It happens that food components (for example, iron or calcium) bind to drug molecules, inactivating them – therefore, for example, drugs for the treatment of osteoporosis must be taken on an empty stomach . There are drugs, the effectiveness and safety of which does not change regardless of food intake, so they can be taken at any convenient time.
Clinical trials study taking drugs not only on an empty stomach or after meals, but also in more specific conditions – for example, with fatty foods or a light snack. This is done both in order to make the study group more homogeneous, and in search of an opportunity to reduce the dose without losing effectiveness. For example, there is evidence that foods high in fat can significantly enhance the effects of lapatinib, a drug used to treat breast cancer. However, while in the instructions for most drugs, you can hardly find more specific instructions than “take on an empty stomach” or “take after meals.”