Final answer:
The nurse upholds the principle of autonomy and nonmaleficence by refusing to administer a placebo pill without the patient's informed consent, ensuring the patient's right to self-determination and avoiding harm.
Step-by-step explanation:
When a nurse refuses to administer a placebo pill to a patient, the ethical principle that is being upheld is the principle of autonomy. This principle asserts that patients have the right to make their own decisions regarding their health care, based on full disclosure and understanding of their treatment options. Administering a placebo without the patient's informed consent would undermine this self-determination. The nurse's refusal also aligns with the principle of nonmaleficence, which mandates that health care professionals should not inflict harm on patients. Providing a placebo, which has no therapeutic effect, could be interpreted as causing psychological harm if the patient believes they are receiving a beneficial treatment when they are not. Professionals in the clinical setting must also adhere to the principles of beneficence, justice, and clinical equipoise to ensure that their actions are ethical and respect the rights and well-being of the patients.