Due to the serious and sometimes fatal overdoses that have occurred when methadone is used to treat chronic pain, the Institute for Safe Medication Practices (ISMP) has issued a report warning of the possible risks. If you are currently taking methadone or considering taking it in the future, please be sure to read this alert carefully. It would also be a good idea to either bookmark it or print it out so you can refer to it as needed.
Methadone is a tricky medication that differs from other opioids in a number of ways:
• Methadone remains in the body long after its analgesic effect has worn off. Although the pain relief only lasts 4–8 hours, some of the drug may remain in the body for anywhere from 2 days to 2 weeks.
• You may not experience the full analgesic effects of methadone until you've been using it for 3-5 days, so dosages need to be started small and increased much more slowly than other opioids.
• Just because you may have a high tolerence to other opioids doesn't mean you have a high tolerence to methadone. Methadone needs to be started at much lower dosages.
• If you stop taking methadone for three consecutive days, you may lose your tolerence and be at risk for an overdose if you go back to taking your previous dosage.
• Because patients have different absorption rates and metabolism, methadone dosages have to be given with a very individualized approach.
The ISMP has several recommendations for patients taking methadone:
• Take methadone exactly as prescribed. Do not make any changes to how much you take or when you take it without talking with your doctor first.
• If you just started taking methadone, understand that it may take up to five days for you to experience the full pain relieving effect. If it is not providing adequate pain relief after five days, talk with your doctor.
• Do not start or stop taking other medications or dietary supplements without talking to your doctor because methadone interacts with many other drugs. Taking other medicines or dietary supplements may cause less pain relief or may cause a toxic buildup of methadone in the body which could be dangerous or even fatal.
• Do not drink alcoholic beverages when taking methadone.
• Signs of methadone overdose include trouble breathing or shallow breathing; extreme tiredness or sleepiness; blurred vision; inability to think, talk or walk normally; and feeling lightheaded, dizzy or confused. If you experience any of these symptoms, get medical attention right away.
FDA Patient Safety News, (2009, April). Preventing Overdoses when Using Methadone to Treat Chronic Pain. Retrieved April 27, 2009, from US Food & Drug Administration
ISMP Medication Safety Alert, (2008, February 14).Keeping Patients Safe from Iatrogenic Methadone Overdoses. The Institute for Safe Medication Practices. Volume 13, Issue 3, Pages 1-3.