A number of pharmacological agents (medications) are used to treat withdrawal. In general, withdrawal is treated with a drug that is similar to the drug of abuse. In this way, the individual is weaned off the chemical substance slowly. Common medications for alcohol withdrawal include a class of antianxiety drugs known as benzodiazepines, particularly diazepam (brand name Valium) and chlordiazepoxide (Librium). Withdrawal from opiates, such as heroin, opium, morphine, or oxycodone (OxyContin), is often treated with methadone or clonidine. Methadone maintenance is the most common pharmacological treatment of opiate addiction, serving to reduce craving and withdrawal. Naltrexone is also used to reduce craving by blocking the reinforcing effects of both opiates and alcohol.