Quinidine Aluminium hydroxide

Large rises in urinary pH due to the concurrent use of some antacids, diuretics or alkaline salts can cause quinidine retention, which could lead to quinidine toxicity, but there seems to be only one case on record of an adverse interaction (with an alumini-um/magnesium hydroxide antacid). Aluminium hydroxide alone appears not to interact. 

A patient on quinidine who took eight Afy/ow/a tablets daily (aluminium hydroxide gel 200 mg, magnesium hydroxide 200 mg and simeticone 20 mg) for a week and a little over 1 litre of fruit juice (orange and grapefruit) each day developed a threefold increase in serum quinidine levels (from 8 to 25 mg/L) and toxicity. However, note that the grapefruit juice , (p.280) may have contributed. In 6 healthy subjects, this dose oiMylanta for 3 days produced consistently alkaline urine in 4 subjects, and in 5 subjects when combined with fruit juice. ... 

Romankiewicz JA, Reidenberg M, Drayer D, Franklin JE. The noninterference of aluminium hydroxide gel with quinidine sulfate absorption an approach to control quinidine-induced diarrhea. Am Heart J( 97S) 96, 518-20. 

Mauro VF, Mauro LS, Fr er TD, Temesy-Armos PN, Som P. Effect of aluminium hydroxide gel on quinidine gluconate absorption. Ann Pharmacother (1990) 24, 252-4. 

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