What does the abbreviation PR indicate regarding the route of administration?

The abbreviation PR stands for "per rectum," which refers to the method of administering medication through the rectum. This route is commonly used when oral administration is not feasible due to various reasons, such as the patient being unconscious, experiencing vomiting, or needing a rapid effect of the medication. Rectal administration allows for systemic absorption of the drug, and certain medications are formulated specifically for this route.

In the context of medication routes, "per rectal" and "per rectum" are often used interchangeably, but "per rectum" is the medically established terminology. Understanding this term is essential for professionals in healthcare to ensure accurate medication administration and patient safety.

Other routes of administration, such as those suggested by the other options, do not use the abbreviation PR. For example, "per os" refers to oral administration, while "per respiratory" is not a standard term used in medical practice.