Methadone and buprenorphine are sometimes used to treat opiate addiction. Treatment of withdrawal may include methadone and buprenorphine. Medications can include buprenorphine, methadone, or naltrexone. Examples include morphine, fentanyl, oxycodone, tramadol, hydrocodone, and methadone. Many patients are unable to access morphine, methadone or an equivalent opioid. Evidence of effects of heroin maintenance compared to methadone are unclear as of 2010. Renfro admitted to a detective that he was using heroin and methadone. Treatment of opioid-dependent persons with methadone follows one of two routes&colon; maintenance or detoxification. He again entered rehab in February 2001 for addiction to Vicodin, methadone, amphetamines, and alcohol. In December 2007, Eminem was hospitalized after a methadone overdose. An autopsy found that he died from a combination of drugs, including methadone and antidepressants. Irvin later tested positive for methadone and oxymorphone. Between 70-90% of patients who discontinue methadone maintenance will relapse. Afterwards, Irvin tested positive for methadone and oxymorphone. Some analgesics such as methadone and ketobemidone and perhaps piritramide have intrinsic NMDA action.