Can I take magnesium with amoxicillin?

Yes, and the reason, which is a chemistry that belongs to two antibiotic classes and not to penicillins

Can I take magnesium with amoxicillin: yes, taken together freely and at the same meal if convenient, and the reason is worth understanding because it sorts every antibiotic a reader is likely to be prescribed. The interaction between magnesium and antibiotics is chelation: certain antibiotic molecules bind divalent metal ions, magnesium, calcium, iron and zinc, in the gut, forming complexes that are not absorbed, so that the antibiotic taken with a mineral loses a large fraction of its dose and the infection is undertreated. That chemistry belongs to two classes. The tetracyclines, doxycycline, minocycline, lymecycline, prescribed for acne, chest infections and tick-borne illness, chelate strongly and are spaced from magnesium by two hours before or four to six after. The fluoroquinolones, ciprofloxacin, levofloxacin, prescribed for urinary and some serious infections, chelate strongly too and are spaced the same way. Amoxicillin is a penicillin, a different molecular family that does not bind metal ions, and no clinically meaningful interaction between penicillins and magnesium exists, the same being true of amoxicillin's partner in co-amoxiclav, of flucloxacillin and phenoxymethylpenicillin, and of the cephalosporins, cefalexin among them, the macrolides, clarithromycin, erythromycin and azithromycin, metronidazole, trimethoprim and nitrofurantoin, the common UK prescriptions outside the two chelating classes. A reader on amoxicillin keeps their magnesium habit unchanged.

The one practical note about the gut during a course, the standing pharmacist rule, and the pair filed

The one practical note is not an interaction but an addition: many antibiotic courses, amoxicillin and co-amoxiclav prominently, produce antibiotic-associated diarrhoea by disturbing the gut's bacteria, and a magnesium salt with a laxative effect stacks on that, citrate and oxide especially and any salt in surplus, so a reader on a course who is already loose in the gut takes their magnesium as bisglycinate, the salt with the least osmotic effect, at a dose under the level with a meal, or pauses it for the week of the course and resumes after, a mineral with a weeks-long status pool losing nothing from a week's pause, and a reader whose diarrhoea during a course is severe, bloody or persistent sees a doctor for the antibiotic's sake rather than the magnesium's. The standing pharmacist rule applies as always: anyone on regular medication runs the whole cupboard past a pharmacist once, and a pharmacist dispensing an antibiotic will confirm in a sentence which class it is and whether any spacing applies, the tetracyclines and fluoroquinolones being the two they will flag. The pair filed: magnesium with amoxicillin is fine, no chelation and no spacing, the two chelating classes being the tetracyclines and fluoroquinolones spaced by hours, the rest of the common prescriptions unaffected, and the one note being the gut, bisglycinate or a pause during a course that has loosened it, the worked example being the salt that adds nothing to a course's gut effects, 300mg elemental at 80% NRV, £19.99 for 90 days at 22p.

The verdict, fine with a penicillin, spaced from two other classes

Can I take magnesium with amoxicillin: yes, amoxicillin being a penicillin and penicillins not chelating with magnesium, so that no spacing is needed and the habit continues unchanged, the two antibiotic classes that do chelate being the tetracyclines and fluoroquinolones, spaced by two hours before or four to six after, with the cephalosporins, macrolides, metronidazole, trimethoprim and nitrofurantoin unaffected, and the one practical note being that antibiotic diarrhoea and a laxative magnesium salt stack, answered by bisglycinate or a week's pause. The salt that adds nothing to the gut: Futuro Labs Magnesium Glycinate, bisglycinate, 300mg elemental at 80% NRV, £19.99 for 90 days at 22p a day.

What to check on the label

Questions people also ask

Does magnesium affect amoxicillin absorption?

No: amoxicillin is a penicillin, a molecular family that does not bind metal ions, so there is no chelation and no clinically meaningful interaction, and the two can be taken at the same meal.

Which antibiotics should not be taken with magnesium?

The tetracyclines, doxycycline, minocycline and lymecycline, and the fluoroquinolones, ciprofloxacin and levofloxacin, which chelate with magnesium in the gut and lose absorption, spaced by two hours before or four to six after rather than avoided.

Can I take magnesium glycinate with co-amoxiclav or flucloxacillin?

Yes: both are penicillins with no mineral interaction, as are the cephalosporins, macrolides, metronidazole, trimethoprim and nitrofurantoin, the common UK prescriptions outside the two chelating classes.

Should I stop magnesium during an antibiotic course?

Not for an interaction with amoxicillin, but for the gut if the course has caused diarrhoea: a laxative magnesium salt stacks on antibiotic diarrhoea, so switch to bisglycinate under the level or pause for the week and resume after, a weeks-long status pool losing nothing.

How do I know which class my antibiotic is?

Ask the pharmacist dispensing it, who will say in a sentence whether it is a tetracycline or fluoroquinolone needing spacing from minerals, or one of the many classes that need none.

Sources

1. The antibiotic and mineral interaction literature: tetracyclines and fluoroquinolones chelate with divalent cations, magnesium, calcium, iron and zinc, and lose absorption when taken together, while penicillins such as amoxicillin, cephalosporins, macrolides and metronidazole show no such interaction. PubMed record
2. The magnesium and medicines literature: magnesium supplements reduce absorption of tetracycline and quinolone antibiotics, bisphosphonates and levothyroxine when taken together and are spaced from them, while proton-pump inhibitors and some diuretics lower magnesium status, a reason for medical advice in either direction. PubMed record
3. Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnesium Research 2001;14(4):257-262. PubMed record
4. The Food Supplements (England) Regulations 2003 (food supplements are regulated as foods in the UK). https://www.legislation.gov.uk/uksi/2003/1387/contents/made

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