Module 2: Basic Pharmacology of Controlled Drugs and Substances

Lesson 2

Methadone – Precautions

Because of its extended half-life and lipid-soluble properties, methadone can accumulate in body tissues. There is a risk of overdose (even fatal) if the dose is too high or non-prescribed opioids or other substances (e.g. heroin) are consumed.  Methadone’s metabolic processing through the cytochromes P450 isoenzyme processes creates potential for interaction with many other commonly used medications, creating a risk for potentiation or inhibition of expected therapeutic effects. Finally, prolonged QT intervals have been noted in some individuals taking morphine so providers must be diligent in observing for symptoms and must educate patients about substances to avoid while taking methadone. A useful drug-drug interactions app is available for IOS and Android mobile devices.