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Administering medications with food on the stomach or on an empty stomach.

By Luwana Walton, RN

Gayco Nurse Consultant

Why should some medications be administered with food on the stomach?

To reduce side effects. Side effects are unwanted symptoms caused by medical treatment. They are also called “adverse effects” or “adverse reactions”. All medications can cause side effects, particularly if you don’t use them as advised. This includes prescription medications, medications you can buy over the counter, and herbal remedies and supplements.

Side effects can range from mild, such as drowsiness or feeling sick (nausea), to life threatening conditions, anaphylaxis, although these are rare. The risk of getting side effects varies from person to person.

Some medications can irritate the stomach, cause indigestion and cause stomach inflammation or ulcers. Taking them with food will reduce this effect. Food items such as four ounces of milk or a milk product or a snack are usually enough to constitute having food on the stomach. Food on the stomach last up to two hours after eating a meal.

Medications called antacids are taken to prevent heartburn, reflux, and indigestion which usually occur when acid is produced as food enters your stomach. Therefore, these medications are most effective if taken with food on the stomach.

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 medication away too quickly.

Some medications require food on the stomach and gut for the body to absorb them properly into the bloodstream. Medications for diabetes, if taken by mouth, should usually be taken with food on the stomach to reduce blood sugar levels after eating and to avoid hypoglycemia.

Why should some medications be taken on an empty stomach?

Some medications need to be taken “before food” or “on an empty stomach”. This is because food and some drinks can affect the way these medications work. As a general rule, medications that are supposed to be taken on an empty stomach should be taken at least one half an hour before a meal or two hours after a meal. Forgetting these instructions on rare occasions is unlikely to do any harm, but taking these medications regularly with food may mean they don’t work.

Taking some medications at the same time as eating may prevent your stomach and intestines from absorbing the medication, making it less effective. Some foods can interact with your medication, either by increasing or decreasing the amount of medication in the blood to potentially dangerous levels, or levels that are too low to be effective.

Some foods can neutralize the effect of certain medications. Some of the foods or drinks that can interact with medications include:

  • Grapefruit juice
  • Cranberry juice
  • Foods high in vitamin K such as green leafy vegetables
  • Salt substitutes or food supplements high in potassium , such as bananas

If unsure if a medication should be administer with food on the stomach or if the medications should be administered on an empty stomach consult a drug reference.