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.