Which opioid use disorder medication has a high potential for drug interactions and may cause QT prolongation in the elderly?

Methadone is the correct choice due to its pharmacological profile, which includes a significant potential for drug interactions, particularly because it is metabolized by the cytochrome P450 system. This complexity increases the risk of interactions when methadone is combined with other medications that also use the same metabolic pathways.

In addition, methadone is known to potentially cause QT prolongation, which is a concern particularly in elderly patients who may already have other comorbidities or be taking multiple medications. QT prolongation can lead to serious cardiac arrhythmias, making this a critical consideration in clinical practice.

The other medications listed, while they each have their own risk profiles, do not typically carry the same level of concern regarding drug interactions and QT prolongation as methadone. For example, buprenorphine has a lower risk of causing QT prolongation and drug interactions, while naltrexone and topiramate have different therapeutic uses and risk considerations.