Definition of p.r.n.
p.r.n.: Abbreviation meaning "when necessary" (from the Latin "pro re nata", for an occasion that has arisen, as circumstances require, as needed). One of a number of hallowed abbreviations of Latin terms that have traditionally been used in prescriptions.
Some others:
- a.c. = before meals (from "ante cibum", before meals)
- b.i.d. = twice a day (from "bis in die", twice a day)
- gtt. = drops (from "guttae", drops)
- p.c. = after meals (from "post cibum", after meals)
- p.o. = by mouth, orally (from "per os", by mouth)
- q.d. = once a day (from "quaque die", once a day)
- q.i.d. = four times a day (from "quater in die", 4 times a day)
- q._h.: If a medicine is to be taken every so-many hours (from "quaque", every and the "h" indicating the number of hours)
- q.h. = every hour
- q.2h. = every 2 hours
- q.3h. = every 3 hours
- q.4h. = every 4 hours
- t.i.d. = three times a day (from "ter in die", 3 times a day)
- ut dict. = as directed (from "ut dictum", as directed)
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Last Editorial Review: 4/27/2011 5:27:15 PM
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