Order methadone is a medicine that approved by FDA. It is used for internal pain / pain management. It is strictly restricted for those below 16 years old. Some side effects of Order Methadone are vomiting, Headache, Stomach pain, Dry mouth, Sexual problems, Weight gain,Slow breathing, Itchy skin,Heavy sweating. kidney disease lung disease brain tumor head injury This kind of patients are not allowed to take Methadone online. If the effect goes high or becomes dangerous then call 911 for quick treatment.