Discussion
This is the first national study to assess the extent of knowledge about food/beverage/-drug interactions among Jordanian citizens. Drug interactions are one of the major drug-related problems, but usually neglected due to the lack of sufficient knowledge and public awareness (21, 31).
This study revealed that the majority of participants acknowledged the importance of medicinal plants and herbs in treating diseases. This shows an agreement to the findings of similar studies conducted in Morocco (32), Tanzania (33), the United Kingdom (17), and Surinamese migrants in the Netherlands (34). Many scientific studies support the use of plants to treat diseases under medical supervision (35). For example, Aloe vera is useful for wound healing and recovery from burn injury (36), Clove oil (Eugenia caryophyllus ) is used for the relief of toothache (37), and ginger (Zingiber officinale ) is well-known as a reliever of morning sickness and motion sickness (38).
The results of this study showed that participants used medicinal plants and herbs to treat diseases, mainly respiratory tract illnesses or to boost their immunity. Similar findings by Zaffani et al , showed that Italian women used medicinal plants and herbs to boost their immune system and to cure respiratory disorders (39). In addition, our study participants mentioned several plants and herbs that they usually used, including mint (Mentha piperita ), melissa (Melissa officinalis ), garden cress (Lepidium sativum ), cumin (Cuminum cyminum ), fenugreek (Trigonella foenum-graecum ), mugworts (Artemisia vulgaris ), fennel (Foeniculum vulgare ) and turmeric (Curcuma longa ). Those plants are commonly well-known in the Middle East and Jordan, readily available and affordable (40, 41).
One of the most concerning findings of this study was related to the poor level of knowledge among participants regarding some food/beverage/herb-drug interactions. Although the majority of participants in this survey were from the capital Amman and more than half of them had a university degree, their knowledge regarding food/beverage-drug interactions was poor. This also it indicates that the information leaflet provided with drugs is often not read. The knowledge score was calculated for five common drug classes in Jordan (42). The first was about the consumption of excessive amounts of chocolate with antidepressants, particularly monoamine oxidase inhibitors (MAOIs) due to their caffeine content, which could enhance the hypertensive effect of MAOIs (43, 44). The second was about the interaction of tetracycline antibiotics with milk, which is one of the most common interactions that lead to a significant impairment of the antibiotic’s absorption causing a decrease in its serum concentration (45-47). The third was about the need to avoid the consumption of excessive amounts of bananas when taking angiotensin-converting enzyme (ACE) inhibitors antihypertensives which may increase the risk of developing hyperkalemia, due to its high potassium content. Hyperkalemia can cause irregular heartbeat and heart palpitation (48-50). The fourth was about the need to avoid excessive intake of cranberry and cranberry juice concurrently with vitamin K antagonists anticoagulants, such as warfarin, as it may increase the international normalized ratio (INR) and increase the risk of bleeding (51-54). The last point was related to grapefruit, which is known for its numerous interactions with many drugs and sometimes can lead to fatal complications (55-58). The results showing a poor knowledge about food/beverage/herb-drug interactions among participants are consistent with the findings of a study conducted in the United States of America, where it was found that only one-third of medicinal herb users had ever discussed that with their healthcare providers, which leaves the majority without sufficient information (15). The same was also found in a study conducted in the United Kingdom where the women who participated were found to have little knowledge about herb-drug interactions as they rarely disclosed their use of herbs and other medicinal plants to their healthcare providers as well (17).
The lack of sufficient knowledge among Jordanians, emphasizes the need for extensive educational courses, workshops, and continuous awareness programs to highlight the risk of concurrent intake of food, beverages and herbs with drugs, primarily for healthcare providers. Hence, our Jordanian community relay comprehensively on the advice provided by healthcare providers, which would be reflected by their knowledge, awareness, and appropriate use of drugs, as shown by several published studies (17, 20, 39). Interestingly, this aspect was also requested by several healthcare professionals as reported in a study conducted in Lebanon in which pharmacists were interested in getting courses and workshops to help them better understand possible drug interactions (59). As a result, there is a need for proper patient information gathering by community pharmacists, not only by their physicians to help provide better
Many factors were affecting the knowledge score among the study participants, including the education level, as university graduates and postgraduates had higher knowledge levels in comparison with participants who had only a high school certificate or a diploma, which is consistent with other studies (20) In one study conducted in India it was found that professors had good knowledge about food-drug (21). interactions compared to other participants because they had better expertise (20). Moreover, workers in the healthcare sectors had higher knowledge than participants who had other types of jobs or those who are jobless, which is also consistent with studies in the literature (21). Sajid et al . found that clinical pharmacologists had more awareness of food-drug interaction compared to doctors and nurses, and non-medically qualified people had even less awareness (21). On the other hand, unmarried participants had higher knowledge than other participants, which was an interesting finding for the researchers because it was expected that married participants would have better knowledge, particularly if they have children and went through pregnancy, which needs extra care regarding drug interactions (60-62).
In general, Jordanians are aware of the existence of food/beverage/herb-drug interactions. However, they have little knowledge about what food beverages or herbs interact with common medications. This highlights the need to encourage patients to discuss their use of natural products with their healthcare providers, who also need proper education about this matter.