Pharmacy Sig Codes

What are Sig Codes?

Sig codes are important standard prescription abbreviations that doctors and other medical practitioners use in a prescription. While improving technology has decreased the number of handwritten prescriptions issued nowadays, it is vital for pharmacists, pharmacy technicians, and pharmacy school students to know and remember these codes.

List of Sig Codes and Their Abbreviation Meaning

Sig codes indicate medication dosages, measurements, dosage times or frequency, and routes of administration to a pharmacist and a pharmacy technician. What follows is a list of the pharmacy abbreviations and the abbreviation meaning to those familiar with reading written prescriptions and the sig codes they include.

AAA – Affected area application
ac – before meals
ad – right ear
am – in the morning
amp – ampule
amp – ampicillin
APAP – acetaminophen
aq or H2O – water
as – left ear
au – each or both ears
AUD – apply as directed
bid or b.i.d. – twice a day
BOT – bottle
BP – blood pressure
c – with
C or c – 100
cap – capsule
cc – cubic centimeter
cf – with food
CF – cough/cold formula
cm – centimeter
CPM – chlorpheniramine
cr or cre – cream
CR – controlled release
D or d – 500
D/C or d/c – discontinue
DA – delayed action
DAW – dispense as written
dc or d/c – discontinue
DC – diagnosis code
dil – dilute
disp – dispense
dL – deciliter
DM – dextromethorphan
DR – delayed release
DS – double strength
DV – a daily value
EC or e.c. – enteric-coated
ECT – enteric-coated tablet
ER – extended release
fl – fluid
fl oz – fluid ounce
ft – feet
g, gm – gram
gal – gallon
GG -guaifenesin
GGPE – guaifenesin/phenylephrine
gr – grain
gtt – drop
h or hr – hour
HA – headache
HBP – high blood pressure
HC – hydrocodone or hydrocortisone
HCT or HCTZ – hydrochlorothiazide
hs – at bedtime
ht – height
HT or HTN – hypertension
I or i – 1
IM – intramuscular
in – inch
inh – inhalation
INH – isoniazid
inj – injection
IR – immediate release
IT or ITCH – itching
IU or I.U. – international unit
IV – intravenous
K – Potassium
KCl or KCL – Potassium Chloride
kg – kilogram
L or l – liter
L or l – 50
LA – long-acting
lb – pound
liq – liquid
lot – lotion
m – meter
M or m – 1,000
m² – square meters
mcg – microgram
mcL – microliter
MDI – metered dose inhaler
MDP Medrol Dose Pack
mEq – milliequivalent
Mg or Mag – Magnesium
mg – milligram
mg/dL – milligrams per deciliter of blood
mL- milliliter
mm Hg – millimeters of mercury
MTX – methotrexate
MVI – multiple or Multi-Vitamins
N/A or n/a – not available
N&V or N/V – nausea and vomiting
NA – nausea
Na – Sodium
NaCl – salt
NaHCO3 – sodium bicarbonate
NDC – national drug code
NEB or neb – nebulizer
No., no., Nos. or nos. – number/numbers
noct – at night
NPH – N (intermediate) insulin
NPI – National Provider Identifier
npo – nil per mouth
NR, N.R. or NRF – no refill
NS – nasal spray
NS – normal saline (0.9% sodium chloride)
NTG – nitroglycerin
NV – nausea and vomiting
od – right eye
ODT – orally disintegrating tablet
oint – ointment
OP, OPH, OPHT or OPHTH – ophthalmic
os – left eye
OTC – over the counter
ou – each or both eyes
oz – ounce
PA – prior authorization
PB or Pb – phenobarbital
pc – after meals
PCN – penicillin
pct – percent or percentage
PD – pediatric drop
PED – pediatric
PEG – polyethylene glycol
per – by or through
pH – acidity level
pkd – packaged
pkg – package
pkt – packet
pm – afternoon or in the evening
PMS – premenstrual syndrome
PNV – prenatal vitamins
po – by mouth
pp – postprandial (after eating)
PR – per rectum
prn – as needed
PSE – pseudoephedrine
pt – pint
pt or pt. – patient
PTU – propylthiouracil
q – every, each
qam – every morning
qd – daily
qdam – daily in the morning
qd pm – daily in the evening
qh – every hour
q12h – every 12 hours
q2-3h – every two to three hours
q24h – every 24 hours
q2-4h – every two to four hours
q4h – every four hours
q4-6h – every four to six hours
q4° – every four hours
q6° – every six hours
qhs – every night
qid or q.i.d. – four times a day
qod – every other day
qpm – every evening
q 8pm – every day at 8 p.m.
qs, QS or Q.S. – sufficient quantity
qt – quart
QTY or qty – quantity
qw – once a week
R – rectum, rectally
RA – rheumatoid arthritis
RF – refill
Rx – prescription
s – without
SA – sustained action
sc, sq or subq – subcutaneous (under the skin)
sig – signa (prescription directions)
SL or S.L. – sublingual (under the tongue)
SMZ-TMP – sulfamethoxazole/trimethoprim
SOB – shortness of breath
SOD or sod – sodium
sol or soln – solution
SR – sustained release
ss – one half
stat – immediately
sup or supp – suppository
susp – suspension
syr – syrup
SYR – syringe
tab – tablet
tac or TAC – triamcinolone
tud or TUD – take as directed
tat or TAT – until all taken
tbsp – tablespoonful
TCN – tetracycline
tiw or t.i.w. – three times a week
TMP – trimethoprim
top – topical
tr – timed-release
tsp – teaspoonful
tud or TUD – take as directed
U – units
uad or UAD – use as directed
uat or UAT – until all taken
ud – as directed
ut dict – as directed
ung – ointment
UTI – urinary tract infection
V or v – 5
vag – vaginally
w/ – with
w/o – without
WA – while awake
WH – wheezing
wk – week
wt – weight
WZ – wheezing
X or x – 10
X or x – times
x 1 RF – times one refill
X 3 RF – times three refills
XL – extra long
XR – extended release

The Importance of Knowing Sig Codes

Memorizing Sig codes is of the utmost importance for all pharmacy staff designated to the task of filling prescriptions, as some of the most regular job functions carried out by pharmacy techs are decoding doctors’ prescriptions, translating them into dosages, and filling out directions on patients’ medication bottles and packets.

Usage might include combinations of codes e.g “qs ad” – add sufficient quantity to the right ear.

For the above reason, pharmaceutical students can be confident that specific Sig codes will come up during the PTCB or ExCPT exams.

FAQs

What Does ‘Sig’ Mean?

Sig is an abbreviation of ‘signetur,’ a Latin word meaning ‘let it be labeled.’

Why are pharmacy Sig codes important?

Many pharmacies use Sig (or speed) codes to simplify and speed up the data entry process. Sig codes are often already programmed into a pharmacy computer system.

What are Sig codes used for?

Sig codes tell a pharmacy what to mark on a drug’s label. This helps you to know when and how to take the medication.

What pharmacy sig codes are and why they matter

If you are studying pharmacy or working in a pharmacy setting, you will see sig codes on every prescription you handle. A sig code is a short abbreviation that tells the pharmacist or pharmacy technician how a patient should take a medication. The word “sig” comes from the Latin word signa, meaning “write” or “label.” These codes save time, but only if you know what they mean.

Learning sig codes is one of the first practical skills you pick up in a pharmacy technician program or pharmacy school. Getting them wrong can lead to serious medication errors. Getting them right is a basic part of safe pharmacy practice.

Common sig code abbreviations and what they mean

Sig codes follow patterns. Most come from Latin. Once you learn the patterns, new codes become easier to read. The table below covers the most common ones you will see in a retail or hospital pharmacy setting.

Frequency codes

These codes tell the patient how often to take a medication.

QD – once daily
BID – twice daily
TID – three times daily
QID – four times daily
QOD – every other day
Q4H – every four hours
Q6H – every six hours
Q8H – every eight hours
Q12H – every twelve hours
PRN – as needed
HS – at bedtime (from the Latin hora somni)
AC – before meals
PC – after meals
AM – in the morning
PM – in the evening

Route of administration codes

These codes tell you how the medication enters the body.

PO – by mouth (oral)
SL – under the tongue (sublingual)
TOP – applied to the skin (topical)
OU – both eyes
OD – right eye
OS – left eye
AU – both ears
AD – right ear
AS – left ear
IV – into the vein (intravenous)
IM – into the muscle (intramuscular)
SC or SQ – under the skin (subcutaneous)
PR – rectally
NAS – into the nose (nasal)
INH – by inhalation
TD – through the skin (transdermal)

Quantity and dosage form codes

These codes describe how much of the medication to give and what form it is in.

CAP – capsule
TAB – tablet
SOL – solution
SUSP – suspension (a liquid with particles mixed in)
SUPP – suppository
GTT – drop or drops
UNT or U – units (note: “U” alone is on the error-prone list; see below)
MCG or MCG – micrograms
MG – milligrams
ML – milliliters
TSP – teaspoon (about 5 ml)
TBSP – tablespoon (about 15 ml)
SS – one-half
UD or UT DICT – as directed
NR or NRF – no refills
RF – refill
DAW – dispense as written (the prescriber wants the brand-name drug, not a generic)

Sig codes the FDA and ISMP say to avoid

The Institute for Safe Medication Practices, known as ISMP, keeps a list of abbreviations that have caused real patient harm. The FDA also recommends avoiding certain abbreviations for the same reason. You should know these codes because you may still see them on older or handwritten prescriptions, even though modern prescribing guidelines say not to use them.

Error-prone abbreviations to recognize

These are not codes you should use when writing. They are codes you should know so you can catch potential errors when you see them.

U (for units) can be misread as a zero, turning 4U into 40. Write “units” instead.
IU (international units) can be misread as IV (intravenous). Write “international units” instead.
QD (once daily) can be misread as QID (four times daily). Write “daily” instead.
QOD (every other day) can be misread as QD or QID. Write “every other day” instead.
MS, MSO4, MgSO4 are abbreviations for morphine sulfate and magnesium sulfate. Mixing them up can be fatal. Write the full drug name.
D/C can mean either “discharge” or “discontinue.” This ambiguity has led to medications being stopped too early or continued after discharge. Write the full word.
HS can mean “at bedtime” or “half-strength,” depending on context. Write the meaning out in full.
SC or SQ for subcutaneous can be confused with “SL” for sublingual. Many facilities now use “subcut” to avoid this.

Knowing these error-prone codes is part of medication safety training in every accredited pharmacy technician and pharmacist program. If you go on to work in a hospital or clinical setting, you will likely take a formal medication safety course that goes deeper into this topic.

How sig codes appear on a real prescription label

A typical prescription might read: “1 TAB PO BID x 10D PRN pain.” In plain language, that means: take one tablet by mouth twice a day for ten days as needed for pain. Breaking it down piece by piece makes it readable. You do not need to memorize every possible combination before you start a program. You learn these through repetition in the classroom and in your clinical or externship hours.

Here is another example: “GTT II OD TID.” That means: instill two drops in the right eye three times daily. The number comes before the abbreviation for the form. The route follows. The frequency comes last. This structure stays consistent across most prescriptions.

Reading a compound sig

Some sigs are longer because the medication has more specific instructions. A compounded medication (one that a pharmacist mixes from raw ingredients) might have a sig like: “Apply thin film TOP to affected area BID PRN.” That means: apply a thin layer to the skin on the affected area twice a day as needed. You will see this format often in dermatology prescriptions.

Sig codes in electronic prescribing systems

Most pharmacies now use electronic health records and pharmacy management software. These systems often translate sig codes automatically into plain-language patient instructions. But you still need to understand the underlying codes. Errors happen when pharmacy staff accept a computer translation without checking the original sig against the prescriber’s intent.

In some systems, the pharmacy technician enters the sig code directly. The software converts it to printed label text. If the technician enters the wrong code, the label prints wrong and the patient may take the medication incorrectly. This is why sig code accuracy is tested on the Pharmacy Technician Certification Board exam, known as the PTCB exam, and on the ExCPT exam offered by the National Healthcareer Association.

Sig codes and e-prescribing standards

The National Council for Prescription Drug Programs, called NCPDP, sets standards for electronic prescribing in the United States. Its SCRIPT standard includes a structured sig format that breaks the prescription into separate data fields. This reduces ambiguity compared to free-text sigs. Many states now require e-prescribing for controlled substances, which makes this standard increasingly important for anyone entering the field.

Memorization strategies that work

You do not need to sit down and memorize a list all at once. Most students learn sig codes in layers. Start with frequency codes because you will see them on every prescription. Add route codes next. Dosage form codes come after that.

Using flashcards and repetition

Physical or digital flashcards work well for this type of learning. Write the abbreviation on one side and the full meaning on the other. Review them for ten to fifteen minutes a day. Within two to three weeks, most students can read a typical sig without looking anything up.

Practice with real prescription examples

Ask your program instructor for sample prescription labels to decode. Many pharmacy technician textbooks include practice sets. Working through real examples helps you spot patterns faster than reviewing a list alone. Your externship or clinical rotation will reinforce these codes through direct experience.

Group the Latin roots

Several codes share Latin roots. Oculus means eye, which is why OD, OS, and OU all start with O. Auris means ear, which is why AD, AS, and AU all start with A. Once you know the roots, you can often guess a code you have not seen before.

Sig codes and the PTCB exam

If you plan to become a certified pharmacy technician, you will take the PTCB exam. Sig codes appear throughout the exam because they are part of daily pharmacy work. The exam tests whether you can translate a sig into patient instructions and whether you can spot an error-prone abbreviation.

The PTCB exam is computer-based and has 90 questions. You have two hours to complete it. Pharmacy technician programs accredited by the American Society of Health-System Pharmacists, known as ASHP, are designed to prepare you for this exam. Many programs include practice exams that use realistic sig-heavy scenarios.

How this knowledge connects to a pharmacy career

Sig codes are foundational. Every role in a pharmacy requires them: pharmacy technician, pharmacist, pharmacy student on rotation, and pharmacy intern. If you are considering a pharmacy technician program or a Doctor of Pharmacy, called a PharmD, degree, mastering sig codes early gives you a real head start.

Pharmacy technicians handle prescription entry, label generation, and dispensing. All three tasks involve reading and applying sig codes accurately. Pharmacists verify those entries and counsel patients about their instructions. Understanding the code behind the label helps pharmacists catch errors before a medication leaves the pharmacy.

If you are exploring a career in pharmacy, the next step is finding a program that gives you hands-on practice with real prescription workflows from day one. Look for programs with a structured externship component, because that is where sig code knowledge becomes second nature.

Search accredited pharmacy technician programs and PharmD programs to find one that fits your schedule, budget, and career goals.