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Magnesium and prescription medications

5 documented interactions5 moderateModerate evidence for the supplement itself

Magnesium has 5 documented interactions in Magellan’s curated dataset, covering Loop diuretics, Thiazide diuretics, Bisphosphonates (osteoporosis drugs), Potassium-sparing diuretics, Proton pump inhibitors (acid reducers), Quinolone antibiotics and others. Each entry below gives the mechanism as the cited reference states it, the direction the risk runs, how serious that reference treats it, and what to actually do about it — which is, in every case, a conversation with the clinician or pharmacist who manages the prescription rather than a decision you make alone.

What it is. Magnesium is an essential dietary mineral and the second most abundant intracellular cation, serving as a cofactor in hundreds of enzymatic reactions involved in energy metabolism, protein synthesis, and nerve and muscle function. Magnesium glycinate (magnesium bis-glycinate) is an organic magnesium salt chelated with the amino acid glycine, one of several supplement forms used to raise magnesium status.

Where it sits on the evidence. Magellan grades the supplement itself as Moderate evidence, with a typical studied dose of 250–500 mg elemental magnesium/day (sleep trials used 250 mg as bisglycinate or 500 mg; BP analyses center near ~370 mg/day). That grade is about whether it works, not about whether it is safe alongside your medication — the two questions are independent, and this page answers only the second.

Products this covers: Magnesium L-Threonate · Magnesium Glycinate.

How the risks cluster. The entries split across 2 different mechanisms — nutrient level; absorption and timing — and they are not managed the same way: an absorption problem is fixed by separating the doses in time, an additive or opposing effect is not.

Why Magellan covers it at all

Safety and efficacy are separate questions, and this page only answers the first. For the second, the study Magellan’s coverage of Magnesium rests on is:

Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. ↗

“RCT (n=155): 250 mg elemental magnesium as bisglycinate improved insomnia severity versus placebo at 4 weeks (ISI −3.9 vs −2.3, p=0.049; small effect, d=0.2), with greater response in low-dietary-magnesium participants.”

Nature and science of sleep · 2025 · PMID 40918053

A strong result does not make a supplement safe alongside your prescription, and a documented interaction does not mean the supplement does not work. Magellan grades those two things separately, and neither grade moves for a commission.

Check your own list

Magellan’s Medication Safety Check runs entirely on your device — type the medicines you take and it flags every documented interaction in this dataset. Nothing you type is sent anywhere.

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Every documented interaction

Moderate Loop and thiazide diuretics (e.g. furosemide, bumetanide, hydrochlorothiazide, ethacrynic acid)

Direction of the risk: Nutrient level — this entry is at least partly about what happens to your own level of a vitamin or mineral, not only to the drug.

Chronic use of these diuretics increases urinary magnesium loss and can lead to magnesium depletion, which may affect how much supplemental magnesium is needed or how levels should be monitored.

Medicines in this group include: Furosemide (Lasix), Bumetanide (Bumex), Torsemide (Demadex), Hydrochlorothiazide (Hctz, Microzide), Chlorthalidone (Thalitone), Indapamide (Lozol).

Source: Magnesium: Fact Sheet for Health Professionals ↗ · More on this class: diuretics

What to do: Tell the prescriber who manages your diuretic and ask whether electrolyte and kidney-function labs should be rechecked after any change.

Moderate Oral bisphosphonates (e.g. alendronate)

Direction of the risk: Absorption and timing — taken together, less of one of the two is absorbed. The entry below says which, and separating the doses is usually the fix.

Magnesium can bind bisphosphonates in the gut and reduce their absorption; separate doses by at least 2 hours before or after the bisphosphonate.

Timing the source specifies: Separate doses by at least 2 hours before or after the bisphosphonate.

Medicines in this group include: Alendronate (Fosamax), Risedronate (Actonel), Ibandronate (Boniva), Zoledronic acid (Reclast, Zometa).

Source: Magnesium: Fact Sheet for Health Professionals ↗ · More on this class: other drug classes

What to do: Bisphosphonates already have strict dosing rules — on waking, with plain water, upright, nothing else by mouth for 30–60 minutes. Keep the supplement well outside that window and confirm the interval with your pharmacist.

Moderate Potassium-sparing diuretics (e.g. amiloride, spironolactone)

Direction of the risk: Nutrient level — this entry is at least partly about what happens to your own level of a vitamin or mineral, not only to the drug.

These diuretics reduce urinary excretion of magnesium and can raise magnesium levels; combining with magnesium supplements may increase the risk of elevated magnesium, particularly with impaired kidney function.

Medicines in this group include: Spironolactone (Aldactone), Eplerenone (Inspra), Amiloride (Midamor), Triamterene (Dyrenium).

Source: Magnesium: Fact Sheet for Health Professionals ↗ · More on this class: diuretics

What to do: Tell your prescriber, especially if you have reduced kidney function, and ask whether electrolyte labs should be repeated.

Moderate Proton pump inhibitors (e.g. esomeprazole, lansoprazole, omeprazole)

Direction of the risk: Nutrient level — this entry is at least partly about what happens to your own level of a vitamin or mineral, not only to the drug.

Prolonged PPI use (typically over a year) can independently cause low serum magnesium (hypomagnesemia); the FDA advises considering magnesium level checks before long-term PPI therapy, which is relevant context for anyone also taking magnesium supplements.

Medicines in this group include: Omeprazole (Prilosec), Esomeprazole (Nexium), Lansoprazole (Prevacid), Pantoprazole (Protonix), Rabeprazole (Aciphex).

Source: Magnesium: Fact Sheet for Health Professionals ↗ · More on this class: other drug classes

What to do: Mention it at your next visit or refill. If you have been on an acid reducer long-term, ask whether the labs that are normally followed in that situation are up to date.

Moderate Tetracycline and quinolone antibiotics (e.g. doxycycline, ciprofloxacin, levofloxacin)

Direction of the risk: Absorption and timing — taken together, less of one of the two is absorbed. The entry below says which, and separating the doses is usually the fix.

Magnesium forms insoluble complexes with these antibiotics in the gut, reducing their absorption and effectiveness; take the antibiotic at least 2 hours before or 4-6 hours after magnesium.

Timing the source specifies: Take the antibiotic at least 2 hours before or 4-6 hours after magnesium.

Medicines in this group include: Ciprofloxacin (Cipro), Levofloxacin (Levaquin), Moxifloxacin (Avelox), Doxycycline (Vibramycin), Minocycline (Minocin), Tetracycline (Sumycin).

Source: Magnesium: Fact Sheet for Health Professionals ↗ · More on this class: antibiotics

What to do: Separate the doses — where the source specifies an interval it is stated in the entry above. Never skip or shorten an antibiotic course to take a supplement; if you are unsure about timing, the pharmacist who dispensed the antibiotic can answer it in a minute.

When to seek care urgently

These are the warning signs that go with the medication classes on this page. They are general safety-netting, not a prediction that any supplement will cause them.

If something feels seriously wrong, do not wait for an appointment. Call 911 (US) or your local emergency number.

How to read a severity label

  • Major — the source describes a clinically significant risk — treat this as a combination to clear with a clinician before you start, not after.
  • Moderate — a real, documented interaction that usually calls for monitoring, separating the doses, or a prescriber-led dose change.
  • Minor — documented but usually low-impact, or based on mechanism and animal data rather than human events — still worth naming to your pharmacist.

Severity describes the interaction as the cited reference frames it, not how a specific person will react. A “minor” entry in someone with kidney disease, on five other drugs, can matter more than a “major” one in someone on nothing else.

What this page does not tell you

This is a curated set of interactions with citations — not an exhaustive pharmacology database. An interaction that is absent here has not been ruled out; it may simply not be documented in the references Magellan curates from. Supplements are also not batch-tested for identity or contamination the way prescription drugs are, so what is on the label is a claim rather than a guarantee. And most of these entries come from case reports and mechanistic work rather than randomized trials, which is exactly why the sensible response is a pharmacist review rather than either alarm or dismissal.

Related pages

Supplements and diuretics (water pills)

5 documented interactions across 4 supplements.

Other medication classes with documented supplement interactions

43 documented interactions across 24 supplements.

Supplements and antibiotics

7 documented interactions across 6 supplements.

NOVOS Core (multi-ingredient formula)

8 documented interactions · shares a drug class with Magnesium.

Zinc

3 documented interactions · shares a drug class with Magnesium.

Carnitine (L-carnitine and acetyl-L-carnitine)

7 documented interactions · shares a drug class with Magnesium.

Berberine

5 documented interactions · shares a drug class with Magnesium.

Molecule page: magnesium

The mechanism and the research behind the compound itself.

Molecule page: mglthreonate

The mechanism and the research behind the compound itself.

Supplement–drug safety hub

A–Z of every supplement and drug class in this dataset, plus how to read an interaction.

The evidence-graded supplement guide

What the research actually shows, graded independently of affiliate commissions.

Questions people actually ask

Can I take Magnesium with Hydrochlorothiazide?

Not without checking with the prescriber or pharmacist first. Magellan's dataset grades this as a moderate interaction: Chronic use of these diuretics increases urinary magnesium loss and can lead to magnesium depletion, which may affect how much supplemental magnesium is needed or how levels should be monitored. (Source: Magnesium: Fact Sheet for Health Professionals.)

How far apart should I take Magnesium and Alendronate?

The cited reference specifies an interval: Separate doses by at least 2 hours before or after the bisphosphonate. Confirm the exact timing with the pharmacist who dispensed the medication, because it depends on the formulation.

How many drug interactions does Magnesium have?

5 interactions are documented in Magellan's curated dataset: 5 moderate. They cover Loop diuretics, Thiazide diuretics, Bisphosphonates (osteoporosis drugs), Potassium-sparing diuretics, Proton pump inhibitors (acid reducers). Absence from this list is not proof of safety — it means no interaction is documented in the references we curate from.

What dose of Magnesium is normally studied?

Magellan lists the typical studied dose as: 250–500 mg elemental magnesium/day (sleep trials used 250 mg as bisglycinate or 500 mg; BP analyses center near ~370 mg/day). Dose matters for interactions — several of the entries on this page describe effects that only appear at supplemental rather than dietary intakes.

Who compiles this. Magellan Longevity is written and edited by Gabriel Radu, DO — a physiatrist (New York license 275110, NPI 1376861765). Interaction entries are curated from clinical references — the NIH Office of Dietary Supplements, NCCIH, MedlinePlus, Mayo Clinic and Memorial Sloan Kettering’s About Herbs among them — and every entry links to the reference it came from so you can check it yourself. Magellan earns affiliate commission on some products; nothing on a safety page is softened, delayed, or omitted because of it. Where a supplement we sell carries a major documented interaction, that is the first thing on the page.
Educational information, not medical advice. Supplements are not intended to diagnose, treat, cure, or prevent any disease. Talk to your physician or pharmacist before starting or stopping anything, especially if you are pregnant, nursing, or taking prescription medication. Open Magnesium L-Threonate in the Magellan store →