Is methadone a special risk for overdose? How is it different from other opioids?
Methadone deaths jumped 390% between 1999 and 2004. Methadone was responsible for 13% of drug-related deaths in 2004, even though it is not prescribed nearly as often as other types of drugs. One reason may be the unique way the drug accumulates in the body. Methadone provides pain relief for only 4-8 hours, but its effect on suppressing breathing may last for 2-3 days when a patient takes it for the first time. Patients need plenty of time to develop a tolerance to the breathing depressant effect of methadone. Any controlled substance can be hazardous when used outside of medical direction, but it is particularly important never to take more methadone than prescribed. There also appears to be a small group of patients who converted from one opioid to methadone at a level that could be dangerous. This can occur when physicians use a conversion table that suggests an equal dose of two opioids. When this happens, the starting dose of methadone could be high enough to stop respiration.
