Why must some medicines be taken with or after food?

Some medicines need to be taken with or after food. The six main reasons for this are outlined below.

1. To reduce side effects of nausea or vomiting

It’s better to take some medicines that can cause nausea or vomiting after a meal to reduce these side effects. Examples include allopurinol, bromocriptine and madopar.

2. To reduce side effects of stomach irritation, including indigestion, stomach inflammation or ulcers

Some medicines can irritate the stomach, and taking them with food will reduce this effect. Foods such as biscuits or a sandwich, or a glass of milk, is usually enough. Examples include:

3. To treat problems such as heartburn, reflux or indigestion

Medicines called antacids are taken to prevent heartburn, reflux and indigestion, which usually occur when acid is produced as food enters your stomach. Therefore, these medicines are most effective if taken immediately after, or during, a meal.

4. To ensure the medicine is not washed away

Preparations such as mouthwashes, liquid nystatin and miconazole gel for oral thrush or mouth ulcers must be used after meals. This is because eating food washes the medicine away too quickly.

5. To ensure the medicine is absorbed into the bloodstream properly

Some medications require food in the stomach and gut for the body to absorb them properly, such as the HIV medicines ritonavir, saquinavir and nelfinavir.

6. To help the body process the meal

Medicines for diabetes, if taken by mouth, should usually be taken around meal times to reduce blood sugar levels after eating, and to avoid hypoglycaemia (very low blood sugar).

Enzyme supplements, which can be used to help people with chronic pancreatitis, should also be taken with food to help the body process the meal.

Information about your medicine

If you are unsure when or how to take your medication, talk to your GP or pharmacist (chemist). You can also call NHS 111 for advice.

Further information:

Page last reviewed: 05/05/2015

Next review due: 15/05/2018