Methadone, a synthetic opiate medication that blocks the effects of heroin for about 24 hours, has a proven record of success when prescribed at a high enough dosage level for people addicted to heroin. LAAM, also a synthetic opiate medication for treating heroin addiction, can block the effects of heroin for up to 72 hours. Other approved medications are nalox one, which is used to treat cases of overdose, and naltrexone, both of which block the ef fects of morphine, heroin, and other opiates. Several other medications for use in heroin treatment programs are also under study.