Drug Terminology

These are some of the most commonly used drug abbreviations:

a.c. before meals or food
b.i.d. twice daily
h.s. at bedtime
p.c. after meals
p.o. by mouth
p.r.n. as needed
O.D. right eye
O.S. left eye
O.U. each eye
mcg microgram(s)
mg milligram(s)
mEq milliequivalent(s)
ML milliliter(s)
q.o.d. every other day
q.h. every hour
q.4h. every four hours
q.8h. every eight hours
q.i.d. four times a day
q.o.d. every other day
t.i.d. three times a day

Some Dos and Donts in drug prescription:

Don’t - Dos
q.day - q.d.
q. four hours - q.4h.
80 mg - 0.80 mg
five hundred mg - 500 mg