Reproduced with permission
All medical treatments have the potential for adverse secondary effects,
some anticipated and others not. The medical acceptability of such adverse
secondary effects is judged on a risk-benefit basis. This involves assessing
the likelihood of their occurrence, their severity, and the ability to treat
Some secondary effects have moral implications. An assessment of the moral
acceptability of adverse secondary effects requires consideration of
principles, motives, con-sequences, and implications.* The Rule of Double
Effect, introduced into the discipline of moral reasoning by St. Thomas
Aquinas, is particularly useful in evaluating the moral acceptability of
adverse secondary effects.
The Rule of Double Effect furnishes guidance in a variety of situations such
as relieving persistent or intractable pain with addicting narcotics,
administering drugs or performing procedures that have harmful side effects,
treating terminally ill patients with drugs that have the potential to
shorten life, withdrawing burdensome and/or futile interventions even though
these are life-sustaining, or using "terminal (palliative) sedation." The
Rule of Double Effect distinguishes between morally permissible actions that
allow a patient to die and morally impermissible actions that cause a
patient's death. This distinction applies in a variety of situations, but is
crucial in the public policy debates regarding appro-priate end of life
care, euthanasia, and physician-assisted suicide.**
Actions leading to undesirable secondary effects, even if anticipated, can
be permissible when all of the following criteria are met:
1. The primary act must be inherently good, or at least morally
2. The good effect must not be obtained by means of the bad effect.
3. The bad effect must not be intended, only permitted.
4. There must be no other means to obtain the good effect.
5. There must be a proportionately grave reason for permitting the
CMDA endorses these guidelines, fully realizing that not all situations
in patient care can be anticipated or provided for; nor can the intent of
medical caregivers always be discerned with certainty.
* See CMDA statement Moral Complicity
**See CMDA statements Euthanasia and Physician-Assisted Suicide
Approved by the CMDA House of Representatives,
June 10, 2005' unanimously