Methadone detoxification can be a very uncomfortable and taxing experience. Withdrawal Symptoms usually begin between twenty-four and forty-eight hours after the user's last dose of the drug. Common symptoms include: stomach cramps, sweating, nausea, extreme cravings, tremors, irritability, sneezing, fever, anxiety, paranoia, fuzzy-headedness, hallucinations and clinical depression. Additionally, methadone withdrawal symptoms will last much longer than heroin withdrawal symptoms. Depending on the dose of methadone and how long the person has been using methadone, the symptoms can last for several weeks to several months. Professionals in the field of methadone detoxification typically advise the gradual decrease of the drug over a period of time instead of completely stopping all at once.