Day 7: #flecainide has a narrow therapeutic index & requires careful monitoring to avoid arrhythmias or cardiac arrest. Plasma concentration is monitored where there is an increased risk of toxicity eg renal or hepatic impairment, when high doses are needed, or when interacting drugs are used

Day 6: Some severe DDIs if #flecainide is combined with other anti-arrhythmic drugs e.g beta blockers, verapamil, amiodarone (if combined can reduce flecainide dose), or if used with enzyme inhibitors e.g ritonavir (NOT exhaustive)

Day 5: Common ADRs are arrhythmias, dizziness, visual impairment, fatigue. Uncommon nausea & vomiting, GI disorders. Rare arthralgia, impotence, taste disorders (NOT exhaustive). #flecainide cannot be used if structural heart disease or cardiac failure

Day 4 (cont) #flecainide blocks sodium channels in a rate dependent manner. This means that #flecainide binds preferentially to open channels, therefore the effect increases with the rapid activity seen in arrhythmias

Day 1: Experiments to create new drugs in 1960s > modification of amide local anaesthetics & production of a potent anti-arrhythmic agent #flecainide acetate. Licensed US & UK 1980s

7 days of #flecainide starting today

Key point: Clinically relevant concentrations of lamotrigine block predominant cardiac sodium channel isoform NaV1.5.
doi.org/10.1111/epi....

#epilepsy #ILAE #flecainide #lamotrigine #reentry #ventriculartachycardia