Methadone is a narcotic pain reliever commonly used to manage the symptoms of withdrawal. Administration should be done by a medical professional, however, as there are a number of substances that can interact with methadone and result in dangerous side effects. Not all of these interactions are with other medications; taking methadone while suffering from some conditions, such as gastrointestinal diseases, or while taking legal, readily available substances, such as alcohol or grapefruit juice, can also have dangerous consequences. There are more than 800 known interactions with methadone.
When taken alone, some of the serious side effects of methadone include drowsiness, an irregular heartbeat, difficulty breathing and lightheadedness. Consequently, taking this medication alongside others, such as pain relievers, sleeping pills, or muscle relaxants, can produce methadone interactions. Combining methadone with such over-the-counter prescriptions can cause an individual's breathing to slow and with the added drowsiness can be dangerous.
Some of the most common methadone interactions are the most dangerous. While methadone will help control the symptoms of withdrawal in individuals who are coming down off other narcotics, it may not eliminate them entirely. For some, the temptation to try to further eliminate symptoms with other medications may be great. Methadone is still present in the system for some time after outward effects may have worn off, so even if it seems to have stopped managing symptoms before another dose is prescribed to be taken, it is still present and will interact with other medications that may be self administered.
The consumption of alcohol while taking the medication can also cause methadone interactions. The combination can cause thinking to become impaired or difficult as well; it can also cause physical reactions, such as slowing a person's reaction time and breathing and heart rate. In some cases, mixing alcohol and methadone has resulted in death.
Smoking tobacco products can also result in one of the common methadone interactions; the consumption of tobacco alongside methadone can decrease the effectiveness of the medication. Inversely, grapefruit and grapefruit juice can increase the effectiveness of methadone to a level that will make it toxic.
Methadone interactions also occur when an individual has a pre-existing condition. If it is prescribed to a person with a chronic illness of the gastrointestinal tract, for example, it can result in spasms of the muscles in the tract as well as the development of acute inflammatory bowel disease. When given to an individual with a respiratory disease, it can result in difficulty breathing and further depression of the respiratory system. Liver disease, kidney disease, hypotension, and hyperthyroidism can all result in the development of a new condition if the patient starts taking methadone.