For oral use:
The effects of a number of drugs may be reduced or increased by the alkalinisation of the urine (e.g. aspirin or diflunisal) and reduction in gastric pH brought about by sodium bicarbonate.
The following drugs are reported to be susceptible to inactivation on mixing with sodium bicarbonate solution: adrenaline hydrochloride, benzyl penicillin potassium, carmustine, glycopyrronium bromide, isoprenaline hydrochloride, and suxamethonium chloride.
Sodium-containing preparations should be avoided by patients on lithium because sodium is preferentially absorbed by the kidney resulting in increased lithium excretion and reduced plasma levels.
As a precaution for antacids, in order to minimise the risk of interactions affecting pharmacokinetics of concomitantly administered products, drug administrations should be separated by approximately 2 to 3 hours.
Sodium bicarbonate reduces the absorption of a number of other drugs taken concomitantly. These include ACE inhibitors (captopril, enalapril, and fosinapril), antibacterials and antifungals (azithromycin, cefaclor, cefpodoxime, isoniazid, itraconazole, rifampicin, tetracyclines, ketoconazole and the quinolone group of antibacterials); antivirals (atazanivir, fosamprenavir, tipranavir); antihistamines (fexofenadine); bisphosponates, corticosteroids (deflazacort); digoxin, dipyridamole, antiepileptics (gabapentin and phenytoin), ulcer healing drugs (lansoprazole); levothyroxine, mycophenolate, lipid regulating drugs (rosuvastatin); antipsychotics (sulpiride, phenothiazines), chloroquine, hydrochloroquine, and penicillamine. Antacids should be avoided with nilotinib.
Antacids possibly reduce absorption of bile acids.