Doctors prescribe methadone to treat severe pain on a long-term basis, explains MedlinePlus. Patients who are in treatment programs for opiate drug addictions also sometimes take methadone to prevent experiencing withdrawal symptoms. Some brand-name drugs that contain methadone include Methadose, Diskets and Dolophine.
Methadone is in the opiate analgesic class of prescription drugs, notes MedlinePlus. The medication causes the brain and nervous system to process pain differently, thereby relieving symptoms. It comes in tablet, dispersible tablet and liquid forms. A dispersible tablet is dissolvable in liquids, and patients taking methadone in this form should not chew or swallow the medication prior to mixing the tablet in a liquid.
One of the most serious side effects that can occur when taking methadone is severe difficulty breathing; patients should inform their doctors if they have asthma or have ever experienced breathing problems, according to MedlinePlus. Oftentimes, doctors are unwilling to prescribe methadone to these patients. The risk for developing breathing problems is especially high during the first 72 hours after patients begin taking the drug, as well as following dosage increases. Other potential side effects of methadone include headaches, trouble urinating, weight gain, changes in mood and decreased sexual functioning or desire.