Opiates vs. opioids

Opiate refers to drugs derived from the opium poppy (e.g., morphine, codeine).

Opioid refers to opiates, as well as synthetic and semisynthetic drugs with similar properties (e.g., fentanyl, hydrocodone, oxycodone).

MME

Conversions and comparisons between opioids is typically accomplished by estimating the equivalent dose of oral morphine (i.e., MME). For example, 10 mg of oral oxycodone is approximately equal to 15 mg of oral morphine, or 15 MME.6

Online calculators are available to facilitate conversion, but these conversions should never be used without clinical data. Two useful calculators are available at http://www.nyc.gov/html/doh/html/mental/MME.html and http://opioidcalculator.practicalpainmanagement.com/.

Opioids vary greatly in their pharmacokinetic and pharmacodynamic profiles, which in turn are influenced by route of administration and individual tolerability. Comparing dosages across opioids and individuals is challenging.6 Furthermore, dose conversions for chronic pain may be unreliable, because these equivalents were developed in the context of single-dose, acute pain models in opioid-naïve patients.7,8