Large rises in urinary pH due to the concurrent use of some antacids
(such as sodium bicarbonate) can cause the retention of quinidine, which could lead to toxicity
, but there seems to be only one case on record of an adverse interaction (with alum- inium/magnesium hydroxide). Aluminium hydroxide appears not to nteract.
It is difficult to predict which antacids, if any, are likely to interact. Monitor the effects if drugs that can markedly change urinary pH are started or stopped. Adjust the quinidine
dosage as necessary.