The role of the principle of double effect in ethics education at US medical schools and its potential impact on pain management at the end of life

Background: Because opioids can suppress respiratory drive, the principle of double effect (PDE) has been used to justify their use for terminally ill patients. Recent studies, however, suggest that the risk of respiratory depression in typical end-of-life (EOL) situations may be overstated and that heightened concern for this rare occurrence can lead to inadequate treatment of pain. The purpose of this study is to examine the role of the PDE in medical school ethics education, with specific reference to its potential impact on pain management at EOL. Method: After obtaining institutional review board approval, an electronic survey was sent to ethics educators at every allopathic medical school in the USA. Results: One-third of ethics educators felt that opioids were 'likely' to cause significant respiratory depression that could hasten death. Educators' opinions of opioid effects did not influence their view of the relevance of the PDE, with approximately 70% deeming it relevant to EOL care. Only 15% of ethics educators believed that associating the PDE with opioid use might discourage clinicians from optimally treating pain, out of concern for respiratory depression. Conclusion: This study demonstrates that a significant minority of ethics educators believe, contrary to current evidence, that opioids are 'likely' to cause significant respiratory depression that could hasten death in terminally ill patients. Yet, many of those who do not feel this is likely still rely on the PDE to justify this possibility, potentially (and unknowingly) contributing to clinical misperceptions and underutilisation of opioids at EOL.