Poisoning due to class 1B antiarrhythmic drugs. Lignocaine, mexiletine and tocainide.

摘要: Since most of the toxicity associated with class 1B antiarrhythmic drugs is dose-related, this review examines adverse effects seen in both therapeutic practice and accidental or premeditated overdose. Toxicity very common these agents can be life-threatening. A high percentage patients must discontinue therapy because effects. Mexiletine tocainide are structural analogues lignocaine (lidocaine) similar all 3 drugs. With gradual intoxication (the form) central nervous system such as lightheadedness, dizziness, drowsiness confusion first. Seizures respiratory arrest occur. Cardiovascular manifested by progressive heart block, reduced cardiac contraction, hypotension asystole. Both mexiletine may have proarrhythmic Gastrointestinal also common. Shock, hypotension, failure beta-blocker reduce clearance enhance risk during routine therapy. elimination impaired severe liver disease while renal failure. Management largely supportive symptomatic. Lignocaine infusion discontinued decontamination gut case oral preparations recommended. Serious requires intensive care unit admission. Haemodialysis haemoperfusion helpful serious poisoning. In institutions where extracorporeal circulatory assistance available, massive poisoning has been successfully treated intervention. setting prevented close clinical surveillance appropriate dose reduction drug clearance. Because large interindividual variation pharmacokinetic parameters, monitoring recommended if results reported quickly. stereoselective metabolism assays do not distinguish more active isomers. Therapeutic less useful situation.