Aclient rings the call bell to request pain medication. upon performing the pain assessment, the nurse informs the client that she will return with the pain medication. the nurse's promise to return with the pain medication is an example of which principle of bioethics?

It is an example of fidelity in principle of bioethics.  It is sometimes held that no maleficence is a constant duty, that is, one ought never to harm another individual, whereas beneficence is a limited duty. One clear example exists in health care where the principle of beneficence is given priority over the principle of respect for patient autonomy.