What is Pnr status ?

“PNR is short name for ‘Passenger Name Record’. It is a record in the database of Indian Railways computer reservation system (IR-CRS) against which journey details for a passenger, or a group of passengers are saved.” http://www.trainspnrstatus.com/

Ah. I was going to say it means “As needed”, at least when you’re talking about medical records.

300mg PO Q6h PNR

@Seek your thinking of PRN which stands for the Latin phrase pro re nata or as the situation requires.

You are correct. Pre-coffee dyslexia, apparently.