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Medicine, food and alcohol interactions

What to take with food and what to avoid, for common medicine groups — the grapefruit-and-statins, vitamin-K-and-warfarin, calcium-and-levothyroxine kind of question — with timing and alcohol notes. General information, not a substitute for your pharmacist.

General information only, and not exhaustive. This is not medical advice, not a full list of interactions, and not a reason to start, stop or change a medicine. Interactions depend on the exact drug, the dose, your other medicines and your own health — a pharmacist or doctor is the one who decides. Always read the leaflet that came with your medicine, and ask your pharmacist before adding anything, including supplements.

16medicine groups

Food · timing · alcoholcovers

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The interactions people ask about most

The best-known food–medicine pairings. Each links to the fuller page for that group.
Food or drink	Medicine group	Why it matters
Grapefruit	Statins (some)	Grapefruit blocks a gut enzyme, so more of certain statins reaches the blood than the dose intends. Which statins are affected is specific to each one.
Vitamin K (leafy greens)	Warfarin	Warfarin works against vitamin K, so big swings in green-vegetable intake move its effect. The advice is steadiness, not avoidance.
Calcium and iron	Levothyroxine	Calcium and iron bind levothyroxine in the gut and block its absorption, so they are separated from the dose by several hours.
Calcium, iron and dairy	Tetracycline antibiotics	The same binding problem: these antibiotics form a complex with calcium and iron that the gut cannot absorb.
Tyramine (aged cheese, cured meat)	MAOI antidepressants	Older MAOIs plus tyramine-rich foods can cause a dangerous rise in blood pressure — the one dietary interaction that can be an emergency.

Every medicine group

Statins

Statins lower LDL cholesterol by slowing the liver's own cholesterol production, and are prescribed to reduce the long-term risk of heart attack and stroke.

e.g. atorvastatin, simvastatin, rosuvastatin

Metformin

Metformin lowers blood glucose mainly by reducing the amount of glucose the liver releases, and is usually the first medicine used in type 2 diabetes.

e.g. metformin, metformin modified release

Levothyroxine

Levothyroxine replaces the thyroid hormone the body is not making enough of, in an underactive thyroid.

e.g. levothyroxine sodium (thyroxine, T4)

Warfarin

Warfarin thins the blood by blocking the vitamin K-dependent clotting factors, and is used to prevent and treat blood clots.

e.g. warfarin, phenprocoumon, acenocoumarol (vitamin K antagonists)

DOACs (direct oral anticoagulants)

DOACs thin the blood by directly blocking a single clotting factor, and are used to prevent stroke in atrial fibrillation and to treat and prevent venous clots.

e.g. apixaban, rivaroxaban, edoxaban

SSRIs and SNRIs

These antidepressants raise the availability of serotonin (and for SNRIs also noradrenaline) in the brain, and are used for depression and several anxiety conditions.

e.g. sertraline, citalopram, escitalopram

NSAIDs

NSAIDs reduce pain, fever and inflammation by blocking prostaglandin production.

e.g. ibuprofen, naproxen, diclofenac

Proton pump inhibitors

PPIs strongly reduce stomach acid production, and are used for reflux, ulcers and to protect the stomach when other medicines irritate it.

e.g. omeprazole, esomeprazole, pantoprazole

Tetracycline antibiotics

Tetracyclines are broad-spectrum antibiotics used for chest, skin, dental and tick-borne infections, and for acne over longer courses.

e.g. doxycycline, lymecycline, tetracycline

Macrolide antibiotics

Macrolides are antibiotics used for chest, throat, skin and some stomach infections, and are a common alternative for people allergic to penicillin.

e.g. clarithromycin, azithromycin, erythromycin

ACE inhibitors and ARBs

These medicines relax blood vessels by blocking the renin-angiotensin system, and are used for high blood pressure, heart failure and kidney protection.

e.g. ramipril, enalapril, lisinopril

Beta blockers

Beta blockers slow the heart and reduce its workload by blocking adrenaline's effect on it, and are used for heart rhythm problems, angina, heart failure and some other conditions.

e.g. bisoprolol, metoprolol, atenolol

Oral contraceptives

Oral contraceptives prevent pregnancy, mainly by preventing ovulation and by changing cervical mucus and the lining of the womb.

e.g. combined oestrogen and progestogen pills; progestogen-only pills

Iron supplements

Iron supplements restore iron stores when they are depleted, most often after a blood test has shown low ferritin or iron-deficiency anaemia.

e.g. ferrous sulfate, ferrous fumarate, ferrous gluconate

Calcium supplements

Calcium supplements top up dietary calcium, most often in bone health and alongside treatments for osteoporosis.

e.g. calcium carbonate, calcium citrate, calcium with vitamin D

MAO inhibitors

MAO inhibitors block the enzyme that breaks down monoamines such as serotonin, noradrenaline and dopamine, and are used in some depression and, in other forms, in Parkinson's disease.

e.g. phenelzine, tranylcypromine, isocarboxazid; moclobemide (reversible); selegiline

How to use this well

The single most useful habit with any medicine is to read the leaflet once, properly, and to keep an up-to-date list of everything you take — prescription, over-the-counter and supplements — to show your pharmacist. Most interactions are managed not by avoidance but by timing and consistency: separating two things by a few hours, or keeping an intake steady rather than swinging it.

This section exists to explain the common questions in plain language, not to replace that leaflet or that conversation. Where a page here and your leaflet disagree, the leaflet wins, because it is specific to your exact medicine.

Frequently asked questions

Is this a complete list of interactions?

No, and it is not meant to be. It covers the food, drink and timing questions that come up most often for common medicine groups. The complete, authoritative list for your medicine is its own leaflet and your pharmacist.

Can I stop or change my medicine based on this?

No. Nothing here is a reason to change how you take a medicine. If something here worries you, that is a conversation to have with your pharmacist or doctor, who can see your full picture.

Why does it talk about groups instead of brand names?

Because interactions usually belong to the whole drug class, and the same drug is sold under many names. Working in groups — statins, SSRIs, ACE inhibitors — covers the mechanism without pretending every brand is identical. Your leaflet is brand-specific; this is not.

Does grapefruit really matter?

For some medicines, yes, genuinely. Grapefruit blocks an enzyme in the gut that normally breaks down certain drugs, so more of the dose reaches the blood than intended. Which medicines this affects is specific, which is exactly why the individual leaflet is the place to check.

What about supplements?

Supplements interact too — calcium and iron bind some medicines, St John's wort speeds several up, high-dose vitamins can interfere. Tell your pharmacist about everything you take, not only prescription medicines.

Blood test reference ranges · Alcohol units and clearance · Symptoms and nutrients

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