Oral magnesium salts have the properties of antacids therefore it is recommended that this product is not taken within two to four hours of any other medicinal products to minimise interactions.
There is a risk of metabolic alkalosis when oral magnesium salts are given with polystyrene sulphonate resins. Magnesium salts, taken internally, potentiate the effects of competitive neuromuscular blocking drugs such as tubocurarine.
Magnesium salts may interfere with the absorption of many drugs including (but not limited to) ACE inhibitors (captopril, enalapril, fosinopril); antibacterials and antifungals (azithromycin, cefaclor, cefpodoxime, isoniazid, itraconazole, ketoconazole, methenamine, tetracyclines, rifampicin and quinolone antibacterials); antivirals (atazanavir and tipranavir); antihistamines (fexofenadine); bisphosphonates; corticosteroids (deflazacort); dipyridamole; antiepileptics (gabapentin and phenytoin); ulcer healing drugs (lansoprazole); levothyroxine; mycophenolate; rosuvastatin; antipsychotics (sulpiride and phenothiazines); chloroquine and hydroxychloroquine; penicillamine, and digoxin if given concomitantly.
Alkaline urine may result, increasing excretion of aspirin. Magnesium salts possibly reduce absorption of bile acids and may reduce absorption of eltrombopag (give at least 4 hours apart). The plasma concentration of ulipristal may be reduced. Magnesium salts possibly reduce the plasma concentration of erlotinib (give at least 4 hours before or 2 hours after erlotinib).