Methadone cardiovascular

Methadone is a synthetic opioid, clinically available in the U.S. since 1947.8 It exists in the dextro- and levo-rotatory forms with the levo-isoform possessing approximately 8 to 50 times more pharmacological activity.27 34 Methadone acts on the CNS and cardiovascular system producing respiratory and circulatory depression. Methadone also produces miosis and increases the tone of smooth muscle in the lower gastrointestinal tract while decreasing the amplitude of contractions. It is used clinically for the treatment of severe pain and in maintenance programs for morphine and heroin addicts.34... 

Volunteer postaddicts who receive subcutaneous or oral methadone daily develop partial tolerance to the nauseant, anorectic, miotic, sedative, respiratory-depressant, and cardiovascular effects of methadone. Tolerance develops more slowly to methadone than to morphine in some patients, especially with respect to the depressant effects this may be related in part to cumulative effects of the drug or its metabolites. Tolerance to the constipating effect of methadone does not develop as fully as tolerance to other effects. The behavior of addicts who use methadone parenterally is strikingly similar to that of morphine edicts, but many former heroin users treated with oral methadone show virtually no overt behavioral effects. 

Naioxone (Narcan) Surmountably blocks opioid receptors. Has no effect in narcotic-free persons. Treatment of narcotic overdose. Diagnostic agent (for evaluation of addiction) in methadone programs. To reduce postoperative respiratory depression. Induces narcotic withdrawal syndrome (appetite loss, muscle contraction, fever/chills, restlessness, cardiovascular and respiratory symptoms, nausea,vomiting, diarrhea.)... 

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. 

Cardiovascular The effects of levacetylmethadol n = 31) on the QT interval have been studied in a randomized controlled comparison with racemic methadone ( = 22) [84 ]. After 24 weeks, levacetylmethadol caused significant prolongation of the QT interval (0.409 versus 0.418 seconds), while methadone had no effect. There was no statistically significant change in QT dispersion in either group. There were more patients with... 

Cardiovascular A 56-year-old man was successfully switched from methadone 100 mg/day to buprenorphine after methadone-induced torsade de pointes [86 ]. Morphine was used to counteract withdrawal symptoms. The QT interval normalized over the 3 days and remained normal even 12 months later. 

Cardiovascular A 57-year-old man with HIV infection taking abacavir, nevirapine, tenofovir, voriconazole, and methadone developed new-onset seizures [69 ]. An electrocardiogram showed sinus bradycardia and a prolonged QT interval of 690 msec. He had several episodes of torsade de pointes and ventricular tachycardia, which resolved spontaneously. They were accompanied by altered cognition and... 

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