It is common to believe that medicinal plants cannot have harmful effects, but combined with some medications, they can have dangerous effects Kambo.
The consumption of medicinal plants, also called phytotherapy , is widespread among the population to treat all types of ailments. It is estimated that, in Spain, 1 in 3 people use them to treat some condition , such as insomnia, anxiety, overweight or constipation, as well as for preventive treatment.
Due to their perception as a more “natural” treatment and that they can be purchased without a prescription, there is a general perception that these medicinal plants are harmless and do not cause adverse effects.
However, misusing them can be harmful: medicinal plants act as medicines , since their active ingredients can have a biological and evident effect. In this sense, taking these medicinal plants can cause interactions with medications.
Interactions of medicinal herbs with medications
When treating an ailment, medicinal plants act like drugs: the chemical substances that make them up can create biological activity in the human body. This activity can interact with conventional medications through two types of mechanisms:
Pharmacokinetics : they can affect the absorption, distribution, release, metabolism and elimination processes of drugs.
Pharmacodynamics : they can affect the result of the pharmacological action of the medication by enhancing it, minimizing it or producing a homeostatic imbalance.
In addition, these plants are usually consumed with different methods that can also alter these chemical substances and the effect they have on our body , such as heating or boiling them. They are also affected by other external and environmental factors such as the characteristics of the growing soil, humidity, ambient temperature… as well as the part of the plant used (leaves, flowers, roots, seeds).
If we decide to consume plant-based medications in our daily lives, we must inform ourselves about these risks and be alert to consumption that overlaps with medications that may cause harmful interactions, such as anticoagulants, antiepileptics, antiretrovirals or immunosuppressants .
For example, lime blossom is often used to relax, reduce inflammation and mild pain, as well as blood pressure. However, it is recommended not to take it with medications containing lithium, as there may be changes in the way the body excretes it and cause side effects. [3]
On the other hand, valerian is taken to combat nerves and anxiety [4]. In addition, its sedative action stands out, making it easier to fall asleep. In this sense, Valeriana Teva and Valeriana Teva Forte are two food supplements that can be helpful. In addition to its benefits, we must also keep in mind possible effects it may have on the nervous system due to interactions with other medications.
Below, we present the most common interactions and the plants that cause them when taken with certain medications:
Absorption
In most cases, when plant-drug interactions affect absorption, what happens is a reduction in drug levels . This implies, in practice, a lower activity of the drug, so its effect and potential benefits are reduced.
This effect is created because some plants, in conjunction with certain medications, alter the digestive pH and affect motility (synchronized movements of the digestive system) or non-absorbable complexes are formed, which makes their assimilation difficult. Some medicinal plants that can cause alterations in the absorption of medications are:
St. John’s Wort: decreases digoxin levels , reducing its effectiveness.
Aloe vera – has a laxative effect that can reduce absorption and therefore reduce the effectiveness of some medications.
Metabolism
Drug metabolism is the most important mechanism of interactions with medicinal plants, which can occur when taking:
Ginkgo biloba: Increases insulin elimination and, in the long term, reduces blood pressure. It interferes with some proton pump inhibitor medications, which can be used for heartburn, by activating an enzyme (CYP2C19) that inactivates the medication.
Consumption of this herb is contraindicated with antiepileptics, as it may increase the risk of seizures. Long-term treatments with digoxin should be monitored since ginkgo increases its plasma concentration.
Ginseng and St. John’s Wort : can cause enzyme induction. St. John’s Wort can interact with calcium channel blockers, oral contraceptives (reducing their effect) and antiretrovirals, reducing their levels.
Ephedra and guarana : may reduce the effectiveness of insulin and oral antidiabetics.
Elimination
Certain plants can cause a delay in the elimination of other medications from the body. Interactions at the elimination level occur, for example, with:
St. John’s Wort: increases the biliary excretion of irinotecan, thereby reducing its effectiveness.
Angelica: The variety Angelica dahurica contains furanocoumarins, which can delay the elimination of medications used in diabetes.
Nervous system
The main medicinal plants that can interact with medications at the level of the nervous system are:
Valerian : its sedative effect has additive power and would enhance the action of other drugs with these characteristics. Also, together with passionflower, it could enhance the action of antiepileptics.
Kava: is toxic when combined with some anxiolytics and can enhance the effect of sedative medications.
Henbane : increases the anticholinergic effects of medications such as antidepressants or antihistamines.
St. John’s Wort: it can interact with some antidepressant drugs with which it shares a similar mechanism of action and cause serotonin syndrome. It may also interact with some psychotropic medications.
Evening primrose and borage : they can interact with some antipsychotic medications, because of the gamolenic acid they contain.
Immune system
Echinacea and cat’s claw can have an immunostimulating effect, that is , they increase the activity of the immune system, so they could interact with immunosuppressive medications and reduce their effects.
Cardiovascular system
Certain common cardiovascular medications can see their effect altered with the consumption of medicinal plants and natural remedies, so it is very important to inform yourself about this and ask professionals. Some examples are:
Ginkgo, garlic and ginseng : their anticoagulant properties have an additive effect and enhance drugs with the same characteristics.
St. John’s Wort: decreases the anticoagulant effect of certain cardiovascular medications and reduces the levels of some drugs used for atrial fibrillation.
Horsetail and mistletoe : their hypotensive properties increase the effect of drugs with the same characteristics.
Ephedra and licorice : can raise blood pressure, which could interfere with antihypertensive medication.
For all these reasons, the consumption of medicinal plants is a very important aspect to take into account when reviewing and controlling drug treatments. Knowing these interactions will help us improve the safety and effectiveness of the treatment.