<prompt> Naltrexone is used for which of the following function in opioid addiction?prevention of relapseTreatment of withdrawalTreatment of overdosePrevention of withdrawal  <response>: Naltrexone is a pure opiod antagonist. It is used for opiod blockade theory in post addicts mainly for maintainence therapy and mathadone for substitution therapy. Ref: KD Tripati 8th ed. 