You wake up late, grab your medicine, and swallow it with a sip of water. Breakfast can wait. That may seem harmless, especially when you have taken the same pill before.

Yet food can affect how your body handles some medicines. A meal may protect the stomach, reduce nausea, or help the body absorb a drug. With a few medicines, taking the dose and then skipping food can also cause a dangerous drop in blood sugar.

This does not mean every pill belongs with breakfast. Some medicines must be taken before eating. Always follow the directions on your label. Still, the following five deserve extra care.

1. Ibuprofen and similar pain relievers

Ibuprofen, naproxen, and aspirin can irritate the lining of the stomach. Taking them without food may leave you with burning pain, nausea, indigestion, or stomach discomfort.

These medicines can also cause ulcers or bleeding, especially when used in high doses, taken for many days, or combined with alcohol, blood thinners, or steroid medicines. Food may reduce stomach upset, but it cannot remove every risk.

Take ibuprofen or aspirin with food or just after a meal unless your doctor gives other instructions. Seek medical care for black stools, vomiting blood, faintness, or severe stomach pain.¹

2. Prednisone and prednisolone

Prednisone and prednisolone are steroid medicines used for swelling, allergies, breathing problems, and other health conditions. They may irritate the stomach and cause heartburn or nausea.

Taking the dose with food or milk often makes it easier to tolerate. Your prescribed timing will depend on the condition being treated and how often you need the medicine.²

Do not stop a steroid suddenly after taking it for more than a brief period. Your doctor may need to lower the dose over time.

3. Metformin

Metformin is widely used for type 2 diabetes. It often causes nausea, loose stools, stomach pain, or reduced appetite when treatment begins.

Taking metformin with a meal, or just after one, can make these effects less troublesome. Many people take it with their evening meal, though the correct timing depends on the type of tablet and the dosing plan.³

If vomiting or diarrhea becomes severe, contact your doctor. Losing too much fluid can raise the risk of medication-related problems.

4. Potassium supplements

Potassium tablets and liquids can be harsh on the stomach. On an empty stomach, they may cause nausea, vomiting, diarrhea, or abdominal pain.

Take oral potassium with or right after a meal and with the amount of water listed on the label. Swallow long-acting tablets whole unless your pharmacist tells you otherwise.

Never take extra potassium to treat tiredness or muscle cramps without medical advice. Too much potassium can affect the heart, especially in people with kidney disease or those taking some blood pressure medicines.

5. Nitrofurantoin

Nitrofurantoin is an antibiotic often prescribed for urinary tract infections. Taking it with food or a snack helps the body absorb the medicine and lowers the chance of nausea or stomach upset.

Finish the course as prescribed, even if your symptoms improve. Contact a clinician if you develop trouble breathing, yellow skin, severe weakness, or ongoing diarrhea.

What to do before taking any medicine

Read the pharmacy label each time you receive a medicine. “With food” usually means during a meal or soon after it. Some medicines need specific timing before or after food, so follow the directions carefully.

Do not change the timing based only on a general rule. Ask a pharmacist when the label is unclear, when several medicines have conflicting directions, or when a pill keeps upsetting your stomach.

Taking medicine at the correct time is part of the treatment. A small change in timing can make the medicine safer, easier to tolerate, and more likely to work as intended.