Beta blockers such as propranolol or nadolol blunt the effects of adrenaline on the heart and thereby reduce the risk of arrhythmias. Mexiletine, flecainide and ranolazine decrease the late sodium current and are of particular use in the LQT3 form of Romano–Ward syndrome, and mexiletine may also be of benefit in other subtypes. Potassium supplements may be used at times when potassium is being lost such as when experiencing diarrhoea or vomiting, but medications that encourage the retention of potassium such as spironolactone or amiloride may also be required.
