Magnesium and medicines:
acid reducers, diuretics, antibiotics, thyroid.
Magnesium drug interactions come in two kinds. Some medicines, such as long-term acid reducers and certain water pills, lower the magnesium in your body. Others, such as thyroid tablets and some antibiotics, simply need to be taken a few hours apart from magnesium. Here is a clear guide to both, with the exact spacing for each medicine and a simple daily timetable.
This guide is for education. Never stop, skip or change a prescribed medicine without your doctor.
Magnesium drug interactions: the short version
Which medicines interact with magnesium?
Long-term acid reducers (PPIs such as pantoprazole) and loop or thiazide water pills can lower your magnesium. Thyroid tablets, tetracycline and quinolone antibiotics, bone tablets (bisphosphonates) and gabapentin should be taken a few hours apart from magnesium. Most of these can still be used together safely with the right timing.
Magnesium is involved in hundreds of processes in the body and contributes to normal muscle function, normal functioning of the nervous system and the reduction of tiredness and fatigue.1 That is why it matters when a medicine you take every day quietly lowers it.
Medicines that can lower magnesium
- Acid reducers (PPIs) taken for months or years
- Loop water pills (such as furosemide, torsemide)
- Thiazide water pills (such as hydrochlorothiazide, chlorthalidone)
Medicines to space apart from magnesium
- Thyroid tablets (levothyroxine): about 4 hours
- Tetracycline and quinolone antibiotics: 2 hours before, or 4–6 hours after
- Bone tablets (bisphosphonates) and gabapentin: at least 2 hours
Magnesium and medicines: the spacing chart
How far apart should I take magnesium and my medicines?
Take thyroid tablets about 4 hours apart from magnesium. Take tetracycline or quinolone antibiotics at least 2 hours before, or 4 to 6 hours after, magnesium. Keep bone tablets and gabapentin at least 2 hours away. Acid reducers and water pills need no gap, but may need a magnesium check.
| Medicine | Common examples | What happens | What to do |
|---|---|---|---|
| Thyroid tablets | Levothyroxine (thyroxine) | Magnesium can reduce absorption of the tablet | Keep about 4 hours apart |
| Quinolone antibiotics | Ciprofloxacin, levofloxacin, ofloxacin | Magnesium binds the antibiotic in the gut | Antibiotic at least 2 hours before, or 4–6 hours after, magnesium |
| Tetracycline antibiotics | Doxycycline, minocycline, tetracycline | Magnesium binds the antibiotic in the gut | Antibiotic at least 2 hours before, or 4–6 hours after, magnesium |
| Bone tablets (bisphosphonates) | Alendronate, risedronate | Minerals reduce absorption of the tablet | Keep at least 2 hours apart |
| Gabapentin | Gabapentin | Magnesium antacids cut its absorption by about 20% | Take gabapentin at least 2 hours after magnesium antacids |
| Acid reducers (PPIs) | Pantoprazole, omeprazole, esomeprazole, rabeprazole | Long-term use can lower body magnesium | No gap needed; ask about a magnesium test if used for months |
| Loop and thiazide water pills | Furosemide, torsemide, hydrochlorothiazide, chlorthalidone | More magnesium lost in urine | No gap needed; ask your doctor about checking magnesium |
| Potassium-sparing water pills | Spironolactone, amiloride | Less magnesium lost in urine | Check with your doctor before adding magnesium |
The spacing advice comes from the US National Institutes of Health, medicine prescribing information and NHS antibiotic guidance.2,3,4,5 Exact timings can differ slightly by brand, so your pharmacist’s advice for your medicine comes first.
Magnesium and acid reducers (pantoprazole, omeprazole)
Can I take magnesium with pantoprazole?
Yes. Magnesium and pantoprazole can be taken together, and no time gap is needed. The issue runs the other way: taking a proton pump inhibitor (PPI) for months or years can lower your magnesium. If you take one long-term, ask your doctor to check your magnesium level.
Proton pump inhibitors (PPIs), such as pantoprazole, omeprazole, esomeprazole and rabeprazole, are among the most-used medicines in India for acidity and reflux. In 2011, the US Food and Drug Administration reviewed reports of low blood magnesium in people taking PPIs: most cases appeared after about a year of use, some after three months. Levels returned to normal about a week after the PPI was stopped.6
Doctors were advised to consider checking magnesium before and during long-term PPI use, especially for people who also take digoxin or water pills.6 PPIs are thought to reduce how much magnesium the gut absorbs. A 2019 review of 14 studies with over 129,000 people found PPI use was linked to a 44% higher risk of low magnesium.7
Claims are ingredient-based and not specific to any product. Details of each study are in the “About the studies” box at the bottom of this page.
Magnesium and diuretics (water pills)
Do diuretics lower magnesium?
Some do. Loop diuretics such as furosemide and thiazides such as hydrochlorothiazide increase the magnesium you lose in urine. Potassium-sparing diuretics such as spironolactone and amiloride do the opposite and reduce magnesium loss. If you take a water pill long-term, ask your doctor whether your magnesium should be checked.
Diuretics, or water pills, are commonly prescribed for blood pressure, swelling and heart conditions. Loop and thiazide types make the kidneys pass more water and salts, and that includes more magnesium. Potassium-sparing types reduce magnesium loss instead.2
If you take a water pill every day, ask your doctor whether a magnesium blood test makes sense for you. Never change the dose of a water pill yourself.
Magnesium and antibiotics
Can I take magnesium with antibiotics?
With most antibiotics, yes. Two groups need spacing: tetracyclines (doxycycline, minocycline) and quinolones (ciprofloxacin, levofloxacin). Magnesium binds them in the gut so less antibiotic is absorbed. Take these antibiotics at least 2 hours before, or 4 to 6 hours after, magnesium, or pause magnesium during the short course.
Magnesium, calcium, iron and zinc are all “multivalent” minerals that can latch on to tetracycline and quinolone antibiotics and stop them being absorbed. NHS guidance gives the antibiotic 2 hours before these minerals, and 2 to 4 hours after, depending on the antibiotic, and suggests pausing the mineral product during the course where possible.5 Common antibiotics such as amoxicillin and azithromycin are not in these two groups.
Because antibiotic courses are short, the simplest plan is often to pause magnesium for those few days, or take it at bedtime with the antibiotic in the morning.
Magnesium and thyroid tablets (levothyroxine)
How long after levothyroxine can I take magnesium?
Wait about 4 hours. Levothyroxine prescribing information lists magnesium-containing products among those that can reduce its absorption. The easiest routine is thyroid tablet on an empty stomach in the morning and magnesium in the evening, which keeps them well over 4 hours apart.
Thyroid tablets are taken by millions of Indians, and they are sensitive to anything taken close to them. Magnesium, calcium, iron, antacids and multivitamins with minerals can all reduce how much levothyroxine your body absorbs.3
For magnesium and levothyroxine, the good news is that an evening magnesium routine solves this by itself. Take your thyroid tablet first thing in the morning on an empty stomach, and magnesium with dinner or before bed. For more on timing, read our best time to take magnesium glycinate guide.
Other medicines: bone tablets, gabapentin, iron and zinc
What else should not be taken with magnesium?
Keep bone tablets (bisphosphonates such as alendronate) and gabapentin at least 2 hours away from magnesium. Iron and high-dose zinc supplements are best taken at a different time of day. People with kidney disease should take magnesium only on medical advice, because their kidneys may not clear the extra.
- Bone tablets (bisphosphonates): minerals reduce how much of the tablet is absorbed. Take the tablet as directed on an empty stomach, and keep magnesium at least 2 hours away.2
- Gabapentin: a magnesium and aluminium antacid lowered gabapentin absorption by about 20%; its label advises taking gabapentin at least 2 hours after the antacid.4
- Iron and zinc supplements: take them at a different time of day from magnesium, for example iron in the morning and magnesium at night. See our iron-rich foods guide for the food side of iron.
- Antacid gels and laxatives: many already contain magnesium (often as magnesium hydroxide), so count them when you add a supplement. Our how much magnesium per day guide explains the hidden sources.
- Kidney disease: people with reduced kidney function should take magnesium only on medical advice.2
A simple daily timetable for magnesium and medicines
When is the best time to take magnesium if I take other medicines?
For most people, the evening. Thyroid tablets, bone tablets and many other medicines are taken in the morning, so magnesium with dinner or an hour before bed keeps the gaps automatically. Magnesium in the evening also suits sleep.
- Tell your doctor and pharmacistList every medicine and supplement you take, including magnesium, antacids and laxatives.
- Morning, empty stomachThyroid tablet or bone tablet first, with water, as directed.
- Breakfast and the dayOther morning medicines, and iron if you take it.
- Antibiotic courseTake tetracycline or quinolone antibiotics at least 2 hours before magnesium, or pause magnesium for the course.
- EveningMagnesium with dinner or about an hour before bed.
- Long-term acid reducers or water pillsAsk your doctor whether to check your magnesium level.
- Never change a prescription yourselfYour doctor decides on any change to a medicine or its dose.
| Time | What to take | Gap from magnesium |
|---|---|---|
| 7:00 am, empty stomach | Thyroid tablet (levothyroxine) with water | About 14 hours |
| 8:00 am, breakfast | Morning medicines; iron if prescribed | About 13 hours |
| During an antibiotic course | Doxycycline or ciprofloxacin, morning and afternoon doses | At least 2 hours before magnesium, or pause magnesium |
| 9:00 pm, after dinner | Magnesium | — |
Your own timings may differ; your doctor or pharmacist can fit magnesium around your exact medicines.
You take an acid reducer or water pill and notice muscle cramps or spasms, tremors, a racing or irregular heartbeat, or seizures; these can be signs of very low magnesium. People with kidney disease, and anyone pregnant or on several prescription medicines, should check with their doctor before taking magnesium.
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Join the waitlist →Nutrient Gap Finder
Answer a few quick questions about your food, routine, medicines and symptoms to see which nutrients you may be running low on, and which tests to ask your doctor about.
Try the Nutrient Gap Finder →- The FDA review was based on 38 reports to its adverse event system and 15 published cases; in about a quarter of cases, magnesium supplements alone did not correct the level and the PPI had to be stopped.6
- The 2019 review found a 44% higher risk overall, but results differed widely between studies, and the authors called the link still unclear.7
- Antibiotic spacing varies by medicine: NHS guidance gives ciprofloxacin 2 hours before or 4 hours after minerals, and doxycycline 2 hours before or after; some labels advise up to 6 hours after.5
- Bisphosphonate leaflets ask for at least 30 minutes before food, drinks or other medicines; we use the NIH’s more cautious 2-hour gap for magnesium.2
- The gabapentin figure comes from a study with an aluminium and magnesium hydroxide antacid, not a magnesium glycinate supplement.4
Magnesium and medicines, answered simply.
Can I take magnesium with pantoprazole?
Do acid reflux medicines cause low magnesium?
Can I take magnesium with omeprazole?
How long after levothyroxine can I take magnesium?
Can I take magnesium if I have thyroid problems?
Can I take magnesium with antibiotics?
Can I take magnesium with doxycycline?
Can I take magnesium with ciprofloxacin?
Can I take magnesium with amoxicillin or azithromycin?
Do diuretics lower magnesium?
Can I take magnesium with blood pressure medicine?
Can I take magnesium with alendronate?
Can I take magnesium with gabapentin?
Can I take magnesium with iron tablets?
Can I take magnesium with metformin?
What medicines should not be taken with magnesium?
Which medicines cause magnesium deficiency?
Do antacids contain magnesium?
Can a magnesium supplement fix low magnesium from PPIs?
What is the best time to take magnesium if I take other medicines?
What are the signs of low magnesium from medicines?
Is magnesium glycinate safe with medicines?
Should I stop magnesium while on antibiotics?
Who should not take magnesium supplements?
Studies behind this guide
- European Commission. Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods (magnesium).
- National Institutes of Health, Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals — interactions with medications (bisphosphonates, antibiotics, diuretics, proton pump inhibitors); kidney impairment.
- Levothyroxine sodium tablets: prescribing information (US Food and Drug Administration label), drug interactions section.
- Gabapentin: prescribing information, section 7.3 (aluminium and magnesium hydroxide antacid: bioavailability reduced by about 20%; take gabapentin at least 2 hours after).
- NHS Scotland Right Decisions. Oral tetracycline and fluoroquinolone interactions: reducing antibiotic treatment failure (2023) — spacing from multivalent cations.
- US Food and Drug Administration. Drug safety communication: low magnesium levels can be associated with long-term use of proton pump inhibitor drugs (PPIs), March 2011; as summarised by Health Sciences Authority, Singapore, 22 August 2011.
- Liao S, Gan L, Mei Z. Does the use of proton pump inhibitors increase the risk of hypomagnesemia: an updated systematic review and meta-analysis. Medicine (Baltimore). 2019;98(13):e15011. PMID 30921222