May cause arrhythmias or cardiac arrest w/ catecholamines (eg, epinephrine & isoproterenol). May worsen hypokalemia & undesirable CV reactions (eg, tachycardia, arrhythmias) w/ xanthine derivatives (eg, theophylline, aminophylline hydrate & diprophylline). May decrease serum K levels which triggers arrhythmias w/ corticosteroids (eg, betamethasone, prednisolone & hydrocortisone Na succinate) or diuretics (eg, furosemide).