What does "pr" indicate in prescription instructions?

The abbreviation "pr" in prescription instructions stands for "per rectum," which indicates that a medication should be administered via the rectum. This route can be used for various medications, including suppositories and enemas, often chosen when the patient is unable to take medications orally or when a rapid effect is needed.

The other routes indicated by the other choices refer to different methods of administration: "per oral" indicates taking medication by mouth; "per transdermal" refers to application through the skin, typically with a patch; and "per intravenous" means the medication is administered directly into the bloodstream via a vein. Therefore, understanding the specific meaning of "pr" is crucial for proper medication administration and patient care.