List of abbreviations used in medical prescriptions

This is a list of abbreviations used in medical prescriptions, including hospital orders (the patient-directed part of which is referred to as sig codes). This list does not include abbreviations for pharmaceuticals or drug name suffixes such as CD, CR, ER, XT (See Time release technology § List of abbreviations for those).

Capitalization and the use of periods are a matter of style. In the list, abbreviations in English are capitalized whereas those in Latin are not.

These abbreviations can be verified in reference works, both recent and older. Some of those works (such as Wyeth 1901) are so comprehensive that their entire content cannot be reproduced here. This list includes all that are frequently encountered in today's health care in English-speaking regions.

Some of these are obsolete (such as the apothecaries' units); others remain current.

Abbreviations which are deprecated by the Joint Commission are marked in red. Those abbreviations which are deprecated by other organizations, such as the Institute for Safe Medication Practices (ISMP) and the American Medical Association (AMA), are marked in orange.

The Joint Commission is an independent, non-profit, non-governmental organization which offers accreditation to hospitals and other health care organizations in the United States. While their recommendations are not binding on U.S. physicians, they are required of organizations who wish accreditation by the Joint Commission.

Table

Key

Not recommended for use in the United States by the Joint Commission

Not recommended for use by other organizations, such as the ISMP (Institute for Safe Medication Practices))

Abbreviation or symbol	Latin, Greek, or New Latin	English	Possible confusion
aa, āā, ĀĀ	ana	of each
AAA		apply to affected area	abdominal aortic aneurysm
a.c.	ante cibum	before meals
a.c.h.s., ac&hs	ante cibum et hora somni	before meals and at bedtime
a.d.	auris dextra	right ear	A single-storey "a" can be mistaken as an "o" which could read "o.d.", meaning right eye
ad.	adde addatur	add let there be added
add.	adde addatur	add let there be added
ad lib.	ad libitum	Latin, "at one's pleasure"; as much as one desires; freely	Compare pro re nata, "as needed", which by convention includes an aspect of "up to some maximum". Similarly, compare s.o.s., q.l., and q.s.
admov.	admove admoveatur	apply [or] add add; let there be added
ad us.	ad usum	according to custom
æq.	æquales	equal
agit.	agita	agitate (stir or shake)
alt. d., alt. dieb.	alternis diebus	every other day; on alternate days
alt. h., alt. hor.	alternis horis	every other hour; at alternate hours
a.m.	ante meridiem	morning, before noon
amp.	ampulla	ampule (ampul, ampoule)
amt		amount
aq.	aqua	water
aq. bull.	aqua bulliens	boiling water
aq. com.	aqua communis	common water
aq. dest.	aqua destillata	distilled water
aq. ferv.	aqua fervens	hot water
a.l., a.s.	auris laeva, auris sinistra	left ear	"a" can be mistaken as an "o" which could read "o.s." or "o.l", meaning left eye
ATC		around the clock
a.u.	auris utraque	both ears	"a" can be mistaken as an "o" which could read "o.u.", meaning both eyes
BDS, b.d.s.	bis die sumendum	twice daily
bib.	bibe	drink
bis	bis	twice
b.i.d., b.d.	bis in die	twice daily	AMA style avoids use of this abbreviation (spell out "twice a day")
bis ind.	bis indies	twice a day
bis in 7 d.	bis in septem diebus	twice a week
BM		bowel movement
BNF		British National Formulary
bol.	bolus	as a large single dose (usually intravenously)
BP, Ph.Br.	Pharmacopoeia Britannica	British Pharmacopoeia
BS		blood sugar
BSA		body surface area
b.t.		bedtime	mistaken for "b.i.d", meaning twice daily
bucc.	bucca	buccal (inside cheek)
cap., caps.	capsula	capsule
cap.	capiat	let him take (let the patient take)
c.m.	cras mane	tomorrow morning
c.m.s.	cras mane sumendus	to be taken tomorrow morning
c, c.	cum	with (usually written with a bar on top of the "c")
cib.	cibus	food
c.c.	cum cibo	with food [or] cubic centimetre	mistaken for "U", meaning units; also has an ambiguous meaning; use "mL" or "milliliters" (1 cm³ = 1 mL)
cf.	confer	compare
c.n.	cras nocte	tomorrow night
cochl.	cochleare	spoonful
cochl. ampl.	cochleare amplum	an ample spoonful (a tablespoonful)
cochl. infant.	cochleare infantis	a small spoonful (a teaspoonful)
cochl. mag.	cochleare magnum	a large spoonful (a tablespoonful)
cochl. mod.	cochleare modicum	a modest spoonful (a dessert-spoonful)
cochl. parv.	cochleare parvum	a scant spoonful (a teaspoonful)
colet.	coletur	let it be strained
comp.	compositus	compound
contin.	continuetur	let it be continued
cpt.	capiat	let him take (let the patient take)
cr., crm		cream
CST		continue same treatment
cuj.	cujus	of which
c.v.	cras vespere	tomorrow evening
cyath.	cyathus	a glassful
cyath. vinos.	cyathus vinosus	a wine-glassful
D, d.	die [or] dosis	days [or] doses	ambiguous meaning, write out "days" or "doses"
D5LR		dextrose 5% in lactated Ringer's solution (intravenous sugar solution)
D5NS		dextrose 5% in normal saline (0.9%) (intravenous sugar solution)
D5W, D5W		dextrose 5% in water (intravenous sugar solution)
D10W, D10W		dextrose 10% in water (intravenous sugar solution)
da	da	give
DAW		dispense as written (i.e., no generic substitution)
DC, dc, D/C, disc		discontinue [or] discharge	ambiguous meaning
decoct.	decoctum	decoction
det.	detur	let it be given
dieb. alt.	diebus alternis	every other day; on alternate days
dil.		dilute
dim.	dimidius	one-half
d. in p. æ.	divide in partes æquales	divide into equal parts
disp.		dispersible [or] dispense
div.	divide	divide
dL		deciliter
DS		double strength
d.t.d.	dentur tales doses	give of such doses
DTO		deodorized tincture of opium	can easily be confused with "diluted tincture of opium," which is 1/25th the strength of deodorized tincture of opium; deaths have resulted due to massive morphine overdose. Compare laudanum and paregoric.
DW		distilled water [or] dextrose in water (intravenous sugar solution)
elix.	elixir	elixir
e.m.p.	ex modo prescripto	as directed (in the manner prescribed)
emuls.	emulsum	emulsion
et	et	and
EOD		every other day
ex aq.	ex aqua	in water
exhib.	exhibiatur	let it be given
f.	fiat	make; let it be made
f.h.	fiat haustus	make a draught
fl., fld.	fluidus	fluid (usually meaning specifically liquid in health care)
f.m.	fiat mistura	make a mixture
f. pil.	fiat pilula	make a pill
f.s.a.	fiat secundum artem	make according to art
ft.	fiat	make; let it be made
g, gm		gram (modern SI symbol is g, not gm)
garg.	gargarisma	gargle
gr.	granum	grain
gtt(s)	gutta(e)	drop(s)
gutt.	gutta(e)	drop(s)
H		hypodermic
h, hr, hor.	hora	hour
habt.	habeat	let him have
hor. alt.	hora alternis	every other hour (every second hour; at alternate hours)
hor. decub.	hora decubitus	at bedtime
hor. intermed.	horis intermediis	at intermediate hours
hor. tert.	horis tertiis	every third hour
h.s.	hora somni (at the hour of sleep)	at bedtime [or] half-strength	ambiguous (2 meanings, easily conflated); spell out
IBW		ideal body weight (for dosing based on clearance estimation)
ID		intradermal
IJ, inj.	injectio	injection	mistaken for "IV", meaning intravenously
i.m., IM		intramuscular
IN		intranasal	mistaken for "IM", meaning intramuscular, or "IV", meaning intravenously
ind.	indies	daily
inf.	infusum	infusion (extraction) / intravenous infusion
i	unus tabuletta	one tablet
ii	duo tabuletta	two tablets
iii	tres tabuletta	three tablets
IP		intraperitoneal
IT		intrathecal	mistaken for other abbreviations; spell out
IU		international unit	mistaken for "IV" or "10", spell out "international unit"
i.v., IV		intravenous
i.v.p., IVP		intravenous push
IVPB		intravenous piggyback
kg		kilogram
LAS		label as such
lat. dol.	lateri dolenti	to the painful side
lb.	libra	pound
l.c.d.	liquor carbonis detergens	coal tar solution
lin	linimentum	liniment
liq.	liquor	solution
lot.	lotio	lotion
M., m.	misce	mix
mane	mane	in the morning
max.	maximum	maximum
mcg		microgram	Recommended replacement for "µg" which may be confused with "mg"
m.d.u.	more dicto utendus	to be used as directed
mEq		milliequivalent
mg		milligram
mg/dL		milligrams per deciliter
MgSO4		magnesium sulfate	may be confused with "MSO4", spell out "magnesium sulfate"
min.	minimum [or] minim [or] minutum	minimum [or] minim [or] minute
mist.	mistura	mixture
mit., mitt.	mitte	send
mL		millilitre
mod. præscript.	modo præscripto	in the manner directed
MS		morphine sulfate or magnesium sulfate	can mean either morphine sulfate or magnesium sulfate, spell out either
MSO4		morphine sulfate	may be confused with "MgSO4", spell out "morphine sulfate"
nebul, neb.	nebula	a spray (such as for insufflation)- nebulizer
NMT		not more than
noct.	nocte	at night
non rep.	non repetatur	no repeats (no refills)
NPO, n.p.o.	nil per os	nothing by mouth	AMA style avoids use of this abbreviation (spell out "nothing by mouth")
NS		normal saline (0.9%)
1/2NS		half-normal saline (0.45%)
NTE		not to exceed
o 2, o2		both eyes	"O2" usually means oxygen or oxygen therapy
o.d.	omni die	every day (once daily) (preferred to "qd" in the UK)
o.d.	oculus dexter	right eye	"o" can be mistaken as an "a" which could read "a.d.", meaning right ear, confusion with "omni die"
o.m.	omni mane	every morning
omn. bih.	omni bihora	every 2 hours
omn. hor.	omni hora	every hour
o.n.	omni nocte	every night
OPD		once per day
o.s.	oculus sinister	left eye	"o" can be mistaken as an "a" which could read "a.s.", meaning left ear
o.u.	oculus uterque	both eyes	"o" can be mistaken as an "a" which could read "a.u.", meaning both ears
oz		ounce
p.	perstetur	continue
part. æq.	partes æquales	equal parts
per	per	by or through
p.c.	post cibum	after meals
p.c.h.s., pc&hs	post cibum et hora somni	after meals and at bedtime
Ph.Br., BP	Pharmacopoeia Britannica	British Pharmacopoeia
Ph.Eur.	Pharmacopoeia Europaea	European Pharmacopoeia
Ph.Int.	Pharmacopoeia Internationalis	International Pharmacopoeia
pig./pigm.	pigmentum	paint
p.m.	post meridiem	evening or afternoon
p.o.	per os	by mouth or orally	AMA style avoids use of this abbreviation (spell out "orally")
ppt.	præparata	prepared
p.r., PR	per rectum	rectally
p.r.n., PRN	pro re nata	as needed
pt.	perstetur	continue
pulv.	pulvis	powder
p.v., PV	per vaginam	vaginally
q	quaque	every, per
q.1 h, q.1°	quaque 1 hora	every 1 hour (can replace "1" with other numbers)
q4PM		at 4 pm (can replace "4" with other numbers)	mistaken to mean every 4 hours
q.a.d.	quaque alternis die	every other day
q.a.m.	quaque die ante meridiem	every morning (every day before noon)
q.d./q.1.d.	quaque die	every day	mistaken for "QOD" or "qds," spell out "every day" or "daily". AMA style avoids use of this abbreviation (spell out "every day")
q.d.a.m.	quaque die ante meridiem	once daily in the morning
q.d.p.m.	quaque die post meridiem	once daily in the evening
q.d.s.	quater die sumendus	4 times a day	can be mistaken for "qd" (every day)
q.p.m.	quaque die post meridiem	every evening (every day after noon)
q.h.	quaque hora	every hour
q.h.s.	quaque hora somni	every night at bedtime	can be mistaken as "q.h.r." (every hour)
q.i.d.	quater in die	4 times a day	can be mistaken for "qd" or "qod," write out "4 times a day". AMA style avoids use of this abbreviation (spell out "4 times a day")
q.l.	quantum libet	as much as is requisite
q.n.	quaque nocte	every night	can be mistaken as "q.h." (every hour)
q.o.d.	quaque altera die	every other day	mistaken for "QD," spell out "every other day". AMA style avoids use of this abbreviation (spell out "every other day")
q.q.	quaque	every; each
q.q.h.	quater quaque hora	every 4 hours
q.s.	quantum sufficiat (subjunctive), quantum sufficit (indicative)	as much as suffices; a sufficient quantity
q.v.	quantum volueris [or] quod vide	at will [or] which see
QWK		every week
rep., rept.	repetatur	repeats
RL, R/L		Ringer's lactate
Rx, Rx, RX, , ℞	recipe	take (often effectively a noun meaning "prescription"—medical prescription or prescription drug)
rep.	repetatur	let it be repeated
s.	signa	write (write on the label)
s.a.	secundum artem	according to the art (accepted practice or best practice)
SC		subcutaneous	"SC" can be mistaken for "SL," meaning sublingual. See also SQ
sem.	semen	seed
s.i.d.	semel in die	once a day	used exclusively in veterinary medicine
sig.	signa, signetur	write (write on the label)
s	sine	without (usually written with a bar on top of the "s")
sing.	singulorum	of each
SL, s.l.	sub lingua	sublingually, under the tongue
SOB		shortness of breath
sol.	solutio	solution
s.o.s., si op. sit	si opus sit	if there is a need
s.s., SS	semisse	one-half [or] sliding scale	mistaken for "55" or "1/2"
SSI		sliding scale insulin or sliding scale regular insulin	mistaken to mean "strong solution of iodine" or "selective serotonin reuptake inhibitor". See also SSRI
SQ		subcutaneously	"SQ" can be mistaken for "5Q" meaning "5 every dose". See also SC
SSRI		selective serotonin reuptake inhibitor [or] sliding scale regular insulin	ambiguous. Do not abbreviate
st.	stet	let it stand (for example, for settling)
stat	statim	immediately
SubQ		subcutaneously
sum.	sumat [or] sumendum	let him take [or] let it be taken
supp.	suppositorium	suppository
susp.	suspensio	suspension
syr.	syrupus	syrup
tab.	tabella	tablet
tal., t.	talus	such
tbsp		tablespoon
t.d.s., TDS	ter die sumendum	3 times a day
t.i.d., t.d.	ter in die	3 times a day	AMA style avoids use of this abbreviation (spell out "3 times a day")
tinct.	tinctura	tincture
t.i.w.		3 times a week	mistaken for "twice a week"
top.		topical
TPN		total parenteral nutrition
tr, tinc., tinct.	tinctura	tincture
trit.	triturate	grind to a powder
troch.	trochiscus	lozenge
tsp		teaspoon
U		unit	mistaken for a "4", "0" or "cc", spell out "unit"
u.d., ut. dict.	ut dictum	as directed
ung.	unguentum	ointment
USP		United States Pharmacopeia
vag.	vagine	vaginally
w		with
w/a		while awake
w/f		with food (with meals)
w/o		without
X, x		times
YO, y.o.		years old
μg		microgram	mistaken for "mg", meaning milligram
@		at	mistaken for "2"; spell out "at"
>		greater than	mistaken for a "7"
<		less than	mistaken for an "L"
℔	libra	pound
℥	uncia	ounce
ʒ	drachma	dram (drachm)
℈	scrupulus	scruple

Similarity of handwritten letters

Especially in handwritten prescriptions or orders, and most especially in hasty handwriting (which is the usual kind), letter shape can be ambiguous. The example below compares "a" and "o" in a script where both consist of an incoming stroke, a loop from about 12 o'clock, and an outgoing stroke. They differ only in the angle of the latter.

Numerical notation

When expressing a numerical quantity, Roman numerals are commonly used in place of arabic digits so as to avoid confusion. The numbers 1 - 3 (I, II, III), usually written as upper-case Roman numerals, often have the appearance of a capital "T" or a series of capital "T's" with a dot above each "T." They are also sometimes written as lower-case Roman numerals (i, ii, iii).

Currently discouraged practices

• Abbreviating names of drugs
• Using apothecary's units
• Using trailing zeros or not using a leading zero

External links

• Pharmacy-Tech-Resources.com. "Dispense As Written Codes Explained".