Some common prescribing abbreviations are p.o., p.r.n., a.c., u.d., q.i.d., t.i.d. and ung. Most of these abbreviations refer to Latin terms. For example, q.i.d., stands for the Latin term "quater in die," and it means "four times a day," as noted by the Pharmaceutical Care Laboratory of the School of Pharmacy at the University of North Carolina School of Pharmacy.
The meaning of some of the listed abbreviations, such as p.r.n., p.o., ung. and a.c., stand for "as needed" (pro re nata), "by mouth" (per os), "ointment" (ungentum) and "before meals" (ante cibum), as noted by the University of North Carolina School of Pharmacy.
Some other prescription abbreviations are q.d. (every day/daily), q.2h. (every 2 hours), and b.i.d. (twice a day), as noted by MedicineNet. Some prescriptions can refer to drops for the eyes, and a few abbreviations for these types of prescriptions are gtt. (guttae, or drops), o.d. (oculus dexter, or right eye) and o.s. (oculus sinister, or left eye).
When doctors prescribe medications, they use a variety of medical, prescription and drug terms that are often abbreviated or in Latin. There are many different abbreviations used by professionals in the field of healthcare. For example, the medications lamivudine, efavirenz and indinavir are abbreviated as 3TC, EFV and IDV, respectively, as listed by Stanford University.