Methadone arrhythmia with

ATOMOXETINE ANALGESICS-METHADONE, TRAMADOL Risk of arrhythmias with methadone and possible risk of fits with tramadol Uncertain Avoid co-administration of atomoxetine with methadone or tramadol... 

Contraindications to interferon alfa therapy include hepatic decompensation, autoimmune disease, and history of cardiac arrhythmia. Caution is advised in the setting of psychiatric disease, epilepsy, thyroid disease, ischemic cardiac disease, severe renal insufficiency, and cytopenia. Alfa interferons are abortifacient in primates and should not be administered in pregnancy. Potential drug-drug interactions include increased theophylline levels and increased methadone levels. Co-administration with didanosine is not recommended because of a risk of hepatic failure, and co-administration with zidovudine may exacerbate cytopenias. 

There have been another 11 cases showing a direct link between QT interval prolongation and oral methadone maintenance treatment at doses of 14-360 micrograms/ day (15) (16). QT interval prolongation can lead to arrhythmias such as torsade de pointes, especially when high doses of methadone are given intravenously and associated with concomitant use of cocaine and/or medications that inhibit the hepatic clearance of methadone (e.g. antidepressants and antihistamines). 

Methadone undergoes significant hepatic metabolism by N-demethylation and cycliza-tion to form pyrrolidines and pyrroline (23). Propoxyphene is also hepatically metabolized predominantly by N-demethylation and renally eliminated. The metabolite norpropoxy-phene is cardiotoxic and produces arrhythmias and pulmonary edema that have led to reports of cardiac arrest and death (59). This is especially problematic because of the long half-life of norpropoxyphenethat accumulates with repeated doses of the parent drug. Methadone is excreted in the urine but also in the bile (23). 

Cocaine-related torsade de pointes occurred in a patient taking methadone. Ventricular arrhythmias and increased cardiovascular effects have been reported when other patients taking methadone were given cocaine. The cardiovascular effects of cocaine and morphine appear to be similar to those seen with cocaine alone. 

Hanon S, Seewald RM, Yang F, Schweitzer P, Rosman J. Ventricular arrhythmias in patients treated with methadone for opioid dependence. J Interv Card Electrophysiol 2010 28 19-22. 

Kao DP, Hmgney MC, Mehler PS, Krantz MJ (2015) Arrhythmia associated with buprenorphine and methadone reported to the Food and Drug Administration. Addiction 110 1468-1475... 

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