Large rises in urinary pH due to the concurrent use of
acetazolamide could cause the retention of quinidine, which could lead to
quinidine toxicity. Also note that hypokalaemia, which may rarely be caused by
acetazolamide, can increase the
toxicity of QT-prolonging drugs such as
quinidine.
Monitor the effects if
acetazolamide is started or stopped and adjust the
quinidine dosage as necessary. Also consider monitoring potassium to ensure it is within the accepted range.