Final answer:
The ethical principle supporting the nurse's decision not to administer a potentially harmful opioid medication is nonmaleficence, which emphasizes 'do no harm' in healthcare practice. The correct option is 4.
Step-by-step explanation:
The ethical principle that supports the nurse's decision not to administer a potentially life-threatening opioid medication is nonmaleficence. Nonmaleficence is a guiding principle in medicine and healthcare that revolves around the concept of 'do no harm,' ensuring that healthcare professionals act in ways that do not cause harm to patients.
It requires that patients are not subjected to unnecessary risks or harm, and in the case where harm is unavoidable, the potential benefits should outweigh the risks. Therefore, if a nurse believes that administering an opioid medication might lead to death, refraining from administering the drug would be in keeping with the principle of nonmaleficence.