What can not be combined with drugs?

The body is a huge chemical “factory” that produces the widest range of substances, even ethyl alcohol, and nicotinic acid. Food and drugs are also made up of chemical compounds. Once inside a person, they enter into many reactions with each other and with what the “factory” has already produced. We tell you what may be wrong with dairy products, fruit juices, coffee, and other usual components of the diet.

How the drugs work 

Most drugs today are made in laboratories. They are created most often based on substances contained in nature. And then, they conduct clinical trials to ensure that the drug is safe for people and helps prevent diseases or reduce their symptoms. 

Medicines are produced in different forms. Most doctors prescribe pills or liquids be swallowed. The medicine from the mouth enters the stomach, where the digestive juice breaks down and then into the blood. Through the blood, the medicine spreads throughout the body and does its job – it heals a person. 

In this case, drugs can react with other substances or conditions. This may be another medicine, the state of the body itself at the time of administration, as well as food and drinks. Such reactions are called drug interactions: sometimes, it does not affect the work of the active substance in any way but can lead to the development of side effects.

The intake of certain foods and drinks changes the pharmacokinetics of drugs. This term describes everything that the body does with the drug. But there is no exact data on the frequency and prevalence of drug-food interactions in clinical practice, and literature data are limited. For example, taking pills with fruit juice can affect the concentration of the drug in the blood – make it less or more. Accordingly, the effect of the drug will change. It may be insufficient or excessive, which will cause side effects. 

Medicines and food

Dairy. There is no clear prohibition on drinking milk and eating dairy products while taking medication. However, one review of studies accumulated over the past 25 years found that milk and dairy products can interfere with the absorption of antibiotics. They also affect the bioavailability of drugs such as propranolol, omeprazole, and drugs from the NSAID group (for example, ibuprofen). Bioavailability is a parameter that shows how quickly a drug enters the bloodstream and is distributed throughout the body. 

For example, in the instructions for the antibiotic amoxicillin, you can read that the tablets should be taken with water. This should be done before or after meals, but not during meals. For the drug to work as it should, it is better to eat cottage cheese at one time and drink the pill at another. 

If there is a need and need for taking dairy products during antibiotic treatment, it is better to take a break between them for about 4 hours. During this time, the antibiotic will go through a full-fledged process of transforming into an active form and removing decaying products from the body; it is better to refrain from eating any dairy products when treated with antibiotics. Moreover, this measure is temporary. 

Leafy vegetables and herbs. It’s an essential part of a healthy diet; the more salads you eat, the better. But when taking warfarin, you should pay attention to some types of greens. Warfarin is an anticoagulant that prevents blood clots from forming in the blood vessels. And vitamin K reduces the effectiveness of the drug. 

Doctors do not advise dieting while taking warfarin, but they recommend ensuring your diet is about the same. It should contain more vegetables and fruits with a low vitamin K content- bananas, carrots, corn, potatoes, and bell peppers. And fewer – products with a lot of vitamin K. These are, for example, broccoli, kiwi, vegetable juices, and soybeans. 

Medicines and drinks

Grapefruit juice. Eating grapefruit or drinking juice can affect the way medicines work. This often applies to statins – drugs that lower blood cholesterol levels, calcium channel blockers – they treat hypertension, and anticoagulants. 

Drug interactions with grapefruit juice were first reported in 1991 after scientists accidentally discovered a four-fold increase in blood levels of felodipine when taken with grapefruit juice. Further studies have identified similar interactions with more than 85 drugs. The interaction is most pronounced when drinking grapefruit juice before ingesting the drug. However, a cumulative effect can also be observed with regular use of the drink.

Most often, grapefruit juice increases the concentration of drugs in the blood, and the higher it is, the more likely it is to develop side effects. Therefore, avoiding grapefruit in your diet for therapy is best. 

Grapefruit juice blocks the cytochrome P450 enzyme system, especially its subspecies, the CYP3A4 enzyme. Because of this, the concentration of the drug, which the CYP3A4 enzyme should metabolize, rises unpredictably.

Although in some cases, this is unnecessary: ​​for example, new anticoagulants – rivaroxaban, apixaban – do not react with the fruit. Atorvastatin does not interfere with eating grapefruit or drinking juice, but you should be moderate. You shouldn’t drink more than a liter a day.  

Hypericum infusion. It contains the active substance hyperforin. St. John’s wort appears to improve the condition of people with mild depression and is effective in relieving menopausal symptoms such as hot flashes. Despite this, doctors still advise avoiding this herb.

 St. John’s wort reacts with most drugs and often provokes the development of serious side effects. For example, in combination with antidepressants, it can lead to serotonin syndrome. This state of excess serotonin in the body can potentially be life-threatening. When interacting with oral contraception, St. John’s wort weakens the contraceptive effect and can provoke bleeding.

Coffee. Caffeine affects the rate of drug absorption. If you take a tablet with a sip of coffee, the body will quickly break down the tablet. This may reduce the effectiveness of the medicine.  

Caffeine also affects the processes of drug conversion when taken orally. For example, there is evidence that it reduces the concentration of antipsychotics in the blood. Coffee has the same effect on iron preparations, sedatives, hypotensives, and hypnotics, leading to the treatment’s lack of effect. 

The drugs themselves also affect caffeine: they slow down its metabolism in the body. Instead of cheerfulness, conditionally, for an hour and a half, you will be cheerful for five hours. And you will also experience irritation, anxiety, and tachycardia – this is how the side effects of taking caffeine appear.  

The opposite effect is exerted by caffeine on acetylsalicylic acid (aspirin), paracetamol, and ketoprofen preparations. By changing the environment of the stomach towards acidity, caffeine promotes the rapid absorption of these drugs, which can lead to side effects. Or, on the contrary, to improve the effect, in the case of a combination of aspirin and coffee.

In the instructions for some drugs, they mention the undesirable interaction of caffeine and limiting its use while taking the drug. Coffee lovers need to exclude coffee for the entire treatment period with tablet preparations to achieve the maximum effect.

Alcohol and … all other drugs. The use of alcohol with other drugs, especially sleeping pills and sedatives, depresses the functioning of the nervous system. A state of excessive relaxation develops – hypersecretion. During it, a person may feel dizzy, perceive the world around him slowly, or fall unconscious. This carries the risk of death. When drinking too much alcohol, the heartbeat and breathing are disturbed, as the nervous system controls these functions. Therefore, you should not combine alcohol with drugs. It reduces the effectiveness of drugs and leads to toxic substances forming in the body. 

How to take pills, and when is it better to eat

It is best to drink medicines with plain water. It does not affect the work of the drug in the body; it is a neutral environment. 

As for food, in the instructions for the drug, you can find out exactly whether to drink it before or after a meal or whether it should be done with a meal. Some medications must be taken with food to work properly or prevent side effects. 

Most often, medicines should be taken on an empty stomach – check the instructions for the drug if this is the case with your medicines. Or the medicine is drunk after a meal. The interval should be at least 1.5 hours – this is enough for food to pass through the digestive tract and useful substances to be absorbed into the blood. It is best to take tablets with plain water without gas. This is a neutral environment that does not affect the drug’s pharmacokinetics. 

Important to remember

• Medicines react with the food and drink we consume. This can affect how the medicine works in the body.
• Drinking medicine with milk is not a good idea. It impairs the absorption and effectiveness of drugs. It is better to postpone the intake of dairy products or remove it from the diet for the duration of treatment.
• Some medicines for treating heart and blood vessel diseases do not combine well with foods containing a lot of vitamin K and are incompatible with grapefruit juice. You need to watch your diet while taking these drugs.
• Hypericum infusion is not a harmless herbal drink. It is capable of causing side effects when consumed, and when combined with other drugs, it increases the risk of side effects of the latter.
• Coffee reduces the effect of therapy if you drink it with medicine. Wait to drink coffee tablets and postpone drinking them until later so that the medicine enters the bloodstream and begins to act.
• Alcohol is best not taken with any medication. This is fraught with excessive sleepiness and other life-threatening side effects.
• Take medicines with plain water – this is a neutral environment that does not affect them. The combination of the drug with food should be checked according to the instructions for the drug.
• If you doubt the drug’s combination with any product or drink, read the instructions for the drug. If you can’t find the answer to your question, ask your doctor for help.