Explainer: why need to some medicines be taken with food?

By Janet Sluggett, University of South Australia

Have you ever been advised to take a medicine with meals? How about taking a medicine with cola or avoiding grapefruit?

Hundreds of medicines have meals-associated dosing instructions. With 4 out of 5 Australians aged above 50 taking day-to-day medication, most folks will encounter instructions about medicines and meals at some point in their lives – some of which might appear rather strange.

If a medicine is not taken as recommended with respect to meals, the medicine may not have an impact. Worse, it could lead to side effects. The timing of the meal, the size of the meal, and the types of meals and drinks consumed can all impact the body’s response to a medicine.

Absorption of medicines from the gut

Eating meals triggers multiple physiological alterations, including elevated blood flow to the gut, the release of bile, and changes in the pH (acidity) and motility of the gut. These physiological adjustments can influence the amount of medicine absorbed from the gut into the bloodstream, which can then impact on the body’s response to a medicine.

Certain medicines are recommended to be provided with food due to the fact the physiological adjustments following eating can improve the amount of medicine absorbed by the body. Itraconazole capsules (employed to treat specific fungal infections), for instance, should be taken with meals, and in some circumstances acidic drinks such as cola, due to the fact this product demands an acidic environment to be absorbed.

In other circumstances, alterations in gut secretions and the digestive approach can reduce the effectiveness of a medicine. Specific antibiotics, such as phenoxymethylpenicillin (also recognized as penicillin V), are greatest taken on an empty stomach as they can be significantly less efficient soon after prolonged exposure to acidic circumstances.

Skip the breakfast grapefruit when taking particular drugs.
liz west/Flickr, CC BY

Meals can act as a physical barrier to the surface of the gut wall and prevent specific medicines becoming absorbed into the bloodstream.

Certain components of food, such as calcium or iron, might also bind to particular medicines. This can reduce absorption into the bloodstream, and lead to reduced effectiveness. For this purpose, osteoporosis medicines risedronate and alendronate have to be taken on an empty stomach with water only.

Taking certain medicines with food can reduce the danger of side effects. Diabetes medicines such as gliclazide or glimepiride (belonging to the group of medicines recognized as sulfonylureas), for instance, must be taken with food to reduce the danger of low blood sugar.

Taking medicines such as ibuprofen (for pain and inflammation) or metformin (for diabetes) with food is also advised to decrease nausea and stomach upset.

Does size actually matter?

The partnership in between meal size and medicine effect has not been extensively studied. If you need to have to take a medicine with meals and it’s not mealtime, often a snack is sufficient. But for some medicines, the size of the meal is essential. Orlistat, for instance, reduces the absorption of fats from food to assist weight loss, so it is essential to take this medicine with principal meals for optimal effect.

Constantly adhere to the guidance of your wellness specialist.
Taki Steve/Flickr, CC BY

Meal composition can also be critical. Eating foods high in fibre, protein or fat can effect on the absorption of some medicines.

Drinks such as tea, coffee, milk and fruit juice can also affect the way certain medicines act in the body.

Dairy products need to be avoided within 2 hours of taking antibiotics such as ciprofloxacin or norfloxacin, however they can be eaten at other occasions.

You could need to have to avoid grapefruit altogether as it can interfere with the metabolism (processing) of particular medicines in the physique, top to side effects.

Medicine labels demystified

Check medicine labels very carefully for advice about meals or drinks. Unless otherwise advised, tablets or capsules ought to be swallowed with water.

If the label states “take with or soon after food”, it signifies the medicine need to be taken in the course of the meal, or inside half an hour of eating.

To take a medicine “on an empty stomach”, verify you have not eaten in the past 2 hours, and wait at least half an hour right after taking the medicine before consuming once more, unless the label states otherwise.

Finally, it is crucial to take medicines at the same time every day and be constant with respect to meals and drinks.

If you have particular concerns about taking medicines with meals, ask your pharmacist for additional guidance, check the consumer medicines data (CMI) for each and every medicine, or contact Medicines Line on 1300 633 424.

This write-up was originally published on The Conversation.
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Explainer: why need to some medicines be taken with food?