Taking Medication During Intermittent Fasting

In 30 seconds

Water is allowed during intermittent fasting, but whether a tablet fits your fasting hours depends on its food instructions. Some medicines need food, others an empty stomach, and some diabetes medicines can lower blood sugar if you do not eat. Ask your pharmacist or clinician how to time each one; never skip or change a dose to keep a fast.

• Never skip, delay or change a prescribed dose to protect a fast; ask first.
• Intermittent fasting restricts calories, not fluids, so water for your tablets is allowed.
• Food instructions differ: naproxen goes with or after food, levothyroxine on an empty stomach before breakfast, tea or coffee.
• Insulin and sulfonylureas can cause low blood sugar during a fast and need a plan with your diabetes team.
• Stop the fast and get urgent help if you faint, feel confused or have dizziness that does not go away.

Can you take tablets with water?

Intermittent fasting limits when you eat, not whether you drink. For most people the real question is not how to swallow a tablet but what each medicine’s instructions say about food.

An NIDDK interview with a diabetes specialist notes that intermittent fasting restricts calories, not fluids, so people with diabetes can drink water, diet soda, tea or black coffee during the fast.Source 11

Which medicines need food?

Instructions differ from one medicine to the next, so there is no single rule for every tablet. Three NHS examples show the range.

NHS guidance says naproxen should ideally be taken with or after food to help protect the stomach.Source 22

NHS guidance says levothyroxine should be taken on an empty stomach 30 to 60 minutes before the first meal of the day and before any drink with caffeine, such as tea or coffee, at the same time each day.Source 33

NHS guidance says most people take metformin 1 to 3 times a day with food and that gliclazide tablets are taken after a meal.Source 44Source 55

What do the sources actually say?

No source here tested medicines during a fasting window. The advice combines an NIDDK interview with a diabetes specialist, for diabetes medicines, with NHS pages for individual medicines, which describe food instructions but not fasting. That supports clear questions to ask, not a rule for every medicine.Source 11Source 22Source 33

For diabetes medicines, the NIDDK interview is more specific about who needs extra care and which medicines matter most.

In the NIDDK interview, the specialist advises extra caution, or not fasting, for people on insulin or sulfonylureas, people with type 1 diabetes, an A1C of 9% or higher, a heart attack or stroke in the last three months, or a fever in the past week; a clinician should assess safety first.Source 11

The same expert notes that metformin, pioglitazone and DPP-4 inhibitors rarely cause low blood sugar, while SGLT-2 inhibitors and diuretics increase fluid loss and raise the risk of dehydration.Source 11

What are the safety rules?

For the diabetes medicines most linked to low blood sugar and dehydration, see diabetes medicines and intermittent fasting.

Talk to a qualified health professional before fasting if you are pregnant or breastfeeding, under 18, living with or recovering from an eating disorder, have diabetes, take insulin or a medicine affected by meal timing, are an older adult, or are acutely ill. Do not change the dose or timing of any medicine without your clinician. See Blimbi’s safety guide.

Related guides

• What Breaks a Fast? Drinks, Gum and Medicines

  What breaks a fast? Trials allowed water, black coffee and tea, but no calories. Gum is untested; never change a medicine to keep fasting.

• Fasting Before Blood Work: Water, Coffee and How Long

  Fasting before blood work isn't always needed. When it is, follow the lab: what counts as fasting, whether water and coffee are OK, and what to ask if you take medicines.

• Diabetes Medicines and Intermittent Fasting: Risks

  Diabetes medicines and intermittent fasting: which ones can lower blood sugar or raise dehydration risk, and why dose changes need your care team.

• Who Should Not Do Intermittent Fasting Without Advice?

  Who should not do intermittent fasting without advice? Diabetes medicines, pregnancy and eating disorders need care; few data on children or over-60s.

• What is intermittent fasting? How it works

  Intermittent fasting means eating in planned windows and going without calories in between. How it works, the main types and what trials found.

Frequently asked questions

Can I take my tablets with water during the fasting hours?

Yes, water is allowed in intermittent fasting. The question is whether the medicine itself needs food or an empty stomach. Check the leaflet, and ask your pharmacist if its timing clashes with your eating window before changing anything.Source 11Source 22Source 33

Can I stop or reduce my medicine to make fasting easier?

No. Do not stop or change a prescribed medicine on your own. The NIDDK interview recommends individual planning with a clinician, who decides whether any change is needed and how to monitor it.Source 11

Who needs extra care before fasting while on medicines?

People who use insulin or a sulfonylurea, and people with type 1 diabetes, a high A1C, a recent heart attack or stroke, or a recent fever, according to the NIDDK interview. If you take several prescription medicines, review them with your pharmacist or clinician before you start.Source 11

Sources

1. 1

   Fasting Safely with DiabetesMartin M. Grajower. National Institute of Diabetes and Digestive and Kidney Diseases, August 26, 2020.Official guidance

2. 2

   NaproxenNHS. NHS, June 25, 2026.Official guidance

3. 3

   LevothyroxineNHS. NHS, July 6, 2026.Official guidance

4. 4

   MetforminNHS. NHS, August 5, 2026.Official guidance

5. 5

   GliclazideNHS. NHS, August 6, 2026.Official guidance

6. 6

   DehydrationNHS. NHS, May 1, 2026.Official guidance

7. 7

   Low blood sugar (hypoglycaemia)NHS. NHS, August 3, 2023.Official guidance