Mineral and Medicine Interactions: A Reference Table (Thyroid Medicine, Antibiotics, Blood Pressure Medicines, Bisphosphonates and More)
A reference table of mineral and medicine interactions documented by the NHS and MedlinePlus, covering thyroid medicine, antibiotics, bone medicines, diuretics and blood pressure medicines, with when to ask a pharmacist.
Content last updated . This page has not been medically reviewed.
Safety first
Never stop or change a prescribed medicine because of a supplement or because of this table. It lists examples that official pages document, not every interaction. Your pharmacist can check your full list of medicines, over-the-counter products, supplements and salt substitutes. The NHS tells people to tell their doctor about any other medicines, herbal remedies, vitamins or supplements they take. [1] If you are pregnant or breastfeeding, give medicines to a child, are older, or have kidney or liver disease, ask before combining anything. In the US, call Poison Help at 1-800-222-1222 or 911 after a suspected overdose.How to read this table
Each row shows a medicine or medicine group, the mineral involved, what the named source says, and the page it comes from. Two kinds of interaction appear. Absorption interactions change how much of a medicine or mineral gets into the body; spacing detail is on Spacing supplements and medicines. Blood-level interactions change a mineral level in the blood, such as potassium. Evidence labels: label instruction (official medicine or health page) and review. The NHS lists are examples, and the NHS pages say they are not the full list of medicines that may interact.Reference table
| Medicine or group | Mineral or product | What the source says | Source |
|---|---|---|---|
| Levothyroxine (thyroid hormone) | Calcium and iron supplements, antacids | Listed among things that may not mix well; take on an empty stomach 30 to 60 minutes before the first meal of the day. A systematic review found limited evidence that calcium or iron supplements decreased absorption. | [2][3] |
| Doxycycline (antibiotic) | Iron or zinc supplements, antacids | Listed among medicines and supplements that may not mix well with it. | [1] |
| Ciprofloxacin (antibiotic) | Dairy and calcium-added drinks | Leave a gap of at least 2 hours; the calcium can stop the body taking in all the medicine. | [4] |
| Alendronic acid (bone medicine) | Mineral water, milk and other drinks | Not to be taken with still or sparkling mineral water, tea, coffee, juice or milk; these can reduce how much is absorbed. | [5] |
| Iron medicine (ferrous fumarate) | Magnesium, calcium, zinc, other iron, antacids | Doxycycline, ciprofloxacin, antacids, products containing magnesium, calcium, zinc or other iron, and levothyroxine may affect how it works. | [6] |
| Spironolactone (potassium-sparing diuretic) | Potassium supplements and potassium-rich salt substitutes | Supplements containing potassium are listed; it can raise potassium levels and cause hyperkalaemia. | [7] |
| Furosemide (loop diuretic) | Potassium | Medicines or supplements that increase potassium levels are listed among things that may not mix well. | [8] |
| ACE inhibitor (lisinopril) | Potassium supplements and salt substitutes | MedlinePlus lists potassium supplements among products that may interact and says to talk to your doctor before using potassium-containing salt substitutes. | [9] |
| ACE inhibitors, ARBs, potassium-sparing diuretics | Potassium (blood level) | Named among common causes of too much potassium in the blood (hyperkalemia), which may cause dangerous heart rhythms. | [10] |
| Antithyroid medicines | Iodine | High doses of iodine with antithyroid medicines can have an additive effect and could cause hypothyroidism. | [11] |
| Magnesium-containing laxatives and antacids | Magnesium (kidney disease) | Magnesium excess most often occurs with magnesium supplements or laxatives containing magnesium; in advanced kidney disease the risk is higher. | [12][13] |
| Zinc supplements (mineral to mineral) | Copper, iron, magnesium | A long-term excess of zinc can lead to copper, iron or magnesium deficiency; high zinc reduces copper absorption. | [14][15] |
Mineral by mineral, in short
- Calcium. The NHS ciprofloxacin and levothyroxine pages above name calcium. [4][2] MedlinePlus says some medicines might interfere with how the body absorbs calcium and to tell your provider about all supplements and medicines. [16] See Calcium.
- Iron. Named on the levothyroxine and doxycycline pages. [2][1] See Iron absorption.
- Magnesium. Named on the iron medicine page. [6] See Magnesium and medicines.
- Zinc. Named on the doxycycline and iron medicine pages. [1][6]
- Potassium. Named for spironolactone, furosemide and lisinopril, above.
- Antacids and stomach acid. See Minerals and stomach acid.
Special situations
Kidney disease changes mineral handling; see Minerals, supplements and kidney disease. Before surgery, tell the surgical team about all supplements; see Supplements before surgery. For older adults on several medicines, see Minerals for older adults and polypharmacy. Product quality varies; see Quality testing and certifications.What we could not find
Proper evidence not found, in the pages we read, for numeric gaps for most mineral and medicine pairs (the ciprofloxacin and dairy 2-hour gap is the one explicit number). We did not find, in what we read, statements for thiazide diuretics with calcium, or for bisphosphonates with calcium supplements; ask a pharmacist. We searched NHS medicine pages, MedlinePlus and PubMed.Where to read more
How interactions work and Interactions by drug class.Frequently asked questions
Does a mineral interaction mean I must stop my medicine or supplement?
No. Do not stop a prescribed medicine on your own. Ask a pharmacist or prescriber whether a gap or a different product is needed. [1]
Which medicines most often interact with calcium or iron?
In the pages we read, levothyroxine, doxycycline and ciprofloxacin are named, and iron medicine lists several minerals. This is not a full list. [2][1][4]
Why are potassium products a concern with some blood pressure and heart medicines?
Spironolactone can raise potassium levels, and MedlinePlus names ACE inhibitors, ARBs and potassium-sparing diuretics among causes of high blood potassium. [7][10]
Do food and drink matter too?
Yes for some medicines: the NHS names dairy and calcium-added drinks for ciprofloxacin and mineral water for alendronic acid. [4][5]
Who can check my own combination?
A pharmacist can check all your medicines and supplements together. The NHS also says to read the leaflet that comes with the medicine. [2]
References
- NHS. Doxycycline (medicine page). NHS. Doxycycline (medicine page). Read 2026-10-23.
- NHS. Levothyroxine (medicine page). NHS. Levothyroxine (medicine page). Read 2026-10-23.
- Wiesner A et al. Levothyroxine Interactions with Food and Dietary Supplements: A Systematic Review. Pharmaceuticals (Basel). 2021. Wiesner A et al. Levothyroxine Interactions with Food and Dietary Supplements: A Systematic Review. Pharmaceuticals (Basel). 2021. Read 2026-10-23.
- NHS. Ciprofloxacin (medicine page). NHS. Ciprofloxacin (medicine page). Read 2026-10-23.
- NHS. How and when to take alendronic acid. NHS. How and when to take alendronic acid. Read 2026-10-23.
- NHS. Ferrous fumarate (medicine page). NHS. Ferrous fumarate (medicine page). Read 2026-10-23.
- NHS. Spironolactone (medicine page). NHS. Spironolactone (medicine page). Read 2026-10-23.
- NHS. Furosemide (medicine page). NHS. Furosemide (medicine page). Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Lisinopril. MedlinePlus (US National Library of Medicine). Lisinopril. Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Potassium in diet. MedlinePlus (US National Library of Medicine). Potassium in diet. Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Iodine in diet. MedlinePlus (US National Library of Medicine). Iodine in diet. Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Magnesium in diet. MedlinePlus (US National Library of Medicine). Magnesium in diet. Read 2026-10-23.
- Cunningham J, Rodriguez M, Messa P. Magnesium in chronic kidney disease Stages 3 and 4 and in dialysis patients. Clin Kidney J. 2012. Cunningham J, Rodriguez M, Messa P. Magnesium in chronic kidney disease Stages 3 and 4 and in dialysis patients. Clin Kidney J. 2012. Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Zinc in diet. MedlinePlus (US National Library of Medicine). Zinc in diet. Read 2026-10-23.
- NHS. Vitamins and minerals: Others (chromium, copper, magnesium, manganese, molybdenum, phosphorus, potassium, selenium, salt, zinc; page last reviewed 3 August 2020). NHS. Vitamins and minerals: Others (chromium, copper, magnesium, manganese, molybdenum, phosphorus, potassium, selenium, salt, zinc; page last reviewed 3 August 2020). Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Calcium in diet. MedlinePlus (US National Library of Medicine). Calcium in diet. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.