Postmarketing data have linked seven cases of known or suspected fatal cardiac arrhythmias, as well as several other cases of symptomatic arrhythmias, to the medication levomethadyl acetate hydrochloride (ORLAAM), used to treat addiction to heroin and other opiates.

The drug becomes the latest in a string of medications implicated in causing potentially fatal cardiac side effects.

As a result, the U.S. Food and Drug Administration (FDA) informed the drug’s manufacturer, Roxane Laboratories Inc., that it had to revise the labeling of the drug, relegating it to second-tier status. The new labeling will state that "due to its potential for serious and possibly life-threatening, proarrhythmic effects, ORLAAM should be reserved for use in the treatment of opiate-addicted patients who fail to show an acceptable response to other adequate treatments for opiate addiction."

The new labeling will also warn prescribing physicians that ORLAAM is contraindicated in any patient with a known or suspected prolonged QT interval and urges that prior to initiating use of the drug, all patients should have an electrocardiogram performed both before induction of the drug and 12 to 14 days following the initiation of therapy.

In addition, the labeling will now warn doctors to screen patients for any other drug use, including prescription drugs, that may also prolong the QT interval. Because ORLAAM is metabolized through the liver’s cytochrome P450 mechanism, any drug that inhibits this mechanism, and therefore would potentially increase the effects of ORLAAM on the QT interval, is also contraindicated.

In patients currently receiving ORLAAM, an individualized risk-benefit assessment should be undertaken by the physician, and any occurrence of symptoms that are suggestive of an arrhythmia (such as palpitations, dizziness, light-headedness, syncope, or seizures) should prompt immediate evaluation and a comprehensive assessment.

Any adverse events associated with the medication should be reported to both Roxane Laboratories at (800) 962-8364 and the FDA at (800) FDA-1088 or through its Web site at www.fda.gov/medwatch. ▪