Does eating before taking our drugs or taking them after a meal affect the efficacy of the drugs?
A
number of us would have been told we should take our drugs after
eating, on an empty stomach, or not to take certain drugs with certain
foods. What are the factual bases of these instructions?
The
truth is that such instructions are relative and depend on the type of
medication, the requirements accompanying a particular medication, as
well as the type of food we are taking.
Food Triggers Changes In The body
It
is first important to understand that food might trigger changes in our
body. These changes include increasing the blood supply in the gut,
increasing bile and also the level of acidity. These changes that are
linked to our eating habits determine medication absorption. Hence the
food we eat and the drinks we take affect medication and the response of
a person’s body to the medication.
Before or After?
Taking
medication after eating or with food usually means taking medication 30
minutes to one hour after a meal. For medication such as non-steroidal
anti-inflammatory drugs (NSAIDs) (ibuprofen, aspirin), metformin for
diabetes and steroid medication, these need to be taken after eating.
With
a few exceptions, and unless stated otherwise by a doctor, most
anti-malaria medications are also taken with a meal. This is important
because taking medicine after a meal not only ensures that medicine is
absorbed into the bloodstream but also prevents side effects, stomach
irritation and ulcers.
Taking medication on an empty stomach
(before food) means at least two hours after a meal and one hour before a
meal. Some of the medications that are required to be taken on an empty
stomach include Antihistamines, used to treat allergies, thyroid
hormones and bisphosphonates, used for bone protection. They are taken
on an empty stomach because taking them while eating prevents the
stomach from absorbing the medication.
Please note that in
instances where you do not seek directions from the information provided
on medication labels, always refer to a doctor or pharmacist for advice
on taking medicine. The doctor’s extensive knowledge of a patient’s
symptoms, their health history and specific health needs make them the
first-line for advice.
How Some Foods Affect Some Drugs
On
the other hand, some medicines can work better or are affected not only
by the presence or lack thereof of food in the stomach but also the
type of food or drink.
In 1989, a research group discovered that
grapefruit and having grapefruit juice interacts and interferes with
some types of medication. The medication that was found to be affected
include statins that lower cholesterol, an anti-hypertensive medication,
medication for heart arrhythmia, organ-transplant rejection medicines
and anti-anxiety medicine.
An enzyme found in grapefruits known
as CYP3A4 is responsible for reducing the level of absorption of
medicines. This is particularly important as CYP3A4 is involved in the
bioactivation of almost 50 per cent of all drugs. Therefore, when
grapefruit juice is consumed, the effectiveness of the drug is reduced
and it also augments the side effects of the medication.
Patients
who take blood-thinning medication (anticoagulant) like warfarin,
phenprocoumon and acenocoumarol were advised to avoid dietary vitamin K
that can be found in leafy greens as it counteracts the effects of their
medication. However, a recent systematic review later found that the
effects of such foods were only detected for high vitamin K intake.
The
review suggests 118 grams per day of raw lettuce green leaf (equivalent
to about one and a half cups of raw lettuce), 106 grams per day of
cooked broccoli (equivalent to about one and a quarter cups of cooked
broccoli), or 30 grams per day of cooked spinach (equivalent to about
one-eighth of a quarter cup of cooked spinach) as a moderate amount in
your diet.
Hence to ensure the absorption of your medication, it
is best to maintain a consistent diet that is not filled with an
excessive amount of leafy greens.
Alcohol
According to the
U.S Food and Drug Administration (FDA), alcohol should be avoided if
you are taking medication due to an increased risk of adverse effects.
Consulting a doctor before you swallow your medicine with alcohol,
drinking alcohol after taking medication and taking medication after
having an alcoholic drink is important.
The FDA warns that
alcohol taken with antihistamines causes drowsiness. Pain relieving
medication like paracetamol can cause severe liver damage when mixed
with three or more alcoholic drinks, regularly. Also, NSAIDs, (drugs
like diclofenac; a component of most body pain-relieving drugs sold by
pharmacies and drug hawkers) can cause stomach bleeding when frequently
mixed with three or more alcoholic drinks.
In addition, do not
take alcohol with a narcotic analgesic, asthma medication, statins,
vasodilators-nitrates for treating angina, antibiotics, antidepressants,
antipsychotics, sleeping medication (sedatives) and bipolar disorder
medication.
Dairy Products
Dairy products like milk,
yoghurt, cheese or calcium-fortified juices contain calcium which
affects certain antibiotics such as tetracycline and ciprofloxacin.
Calcium and antibiotic interaction occur when calcium binds to
antibiotics and prevents their absorption to fight an infection, Neal
Patel from the Royal Pharmaceutical Society said.
He added, “Even
if the milk affects just half of the drug, you’re only getting half the
dose, which could mean the infection isn’t killed off by the end of the
course.”
However, according to the FDA, it is safe to have a
meal that contains the dairy products in them, especially in small
quantities.
In saying this, the aim is that we improve the
effectiveness and safety of our medication by thinking carefully about
when we take them. The various foods mentioned do not imply that we
completely eliminate them from our diets as they include foods that form
a holistic, nutritional and balanced diet.
Rather, this offers a
guide underpinned by experts advice that will help those taking the
medications listed. Indeed, Dima Qato, a pharmacist and assistant
professor at the University of Illinois, Chicago, who studied food and
drug interaction, advised that “leaving at least two to four hours
between the interacting food or juice and the medication is usually
recommended.”
Tavershima Adongo, a medical consultant with the
Premium Times Centre for Investigative Journalism, said: “When we take
medicines, they act on our bodies and our bodies act on them. These
actions are determined by different factors within our bodies, among
which is the type of food (by which we mean both solid food items and
drinks) we eat around taking our medications.”
He said this is
because food in the body is broken down into its chemical components,
which goes ahead to interact with medicines (which are also chemical
compounds in themselves); like most chemicals would.
“These
interactions, therefore, can serve within the body to enhance behaviours
that aid the action of the drug, delay its actions, complement its
action or completely block its actions.
“When the medication
label says to take with a meal or after a meal, for instance, this
simply implies that fat in the food can either delay or enhance
absorption of such a drug,” Mr Adongo said.
