What details must be included in a PRN medication order?

A PRN (pro re nata or "as needed") medication order is intended to provide clear guidelines for when and how to administer medication based on specific clinical criteria. Including target signs, measurable criteria, frequency, and parameters ensures that the administration of the medication is not only justified but also safe and effective.

The target signs and symptoms provide a clear rationale for the medication, giving healthcare providers a basis to assess whether the condition warrants administration. Measurable criteria help in defining the severity or intensity of symptoms that would trigger medication use, ensuring the treatment is tailored to the patient's current state. Additionally, specifying a frequency prevents overuse or misuse of the medication, while parameters guide the healthcare provider on how to monitor the patient's response to the treatment, ensuring that appropriate adjustments can be made if necessary.

This comprehensive approach maximizes safety and efficacy in medication administration, making option B the most complete and appropriate choice for a PRN order.