Pharmacy sig codes — look one up

Updated August 4, 2026

All 76 exam-relevant sig codes in one searchable table — frequencies, routes, forms, measures, and instructions, with 26 ISMP error-prone codes flagged. Cross-checked against the ISMP list and the 2026 PTCE outline; printable cheat sheets below, no email required.

76 of 76 codes

Code	Meaning	Category	Safety
QD	once daily	Frequency	Never writeuse “daily”
BID	twice daily	Frequency
TID	three times daily	Frequency
QID	four times daily	Frequency
QOD	every other day	Frequency	Never writeuse “every other day”
q12h	every 12 hours	Frequency
q8h	every 8 hours	Frequency
q6h	every 6 hours	Frequency
q4h	every 4 hours	Frequency
QHS	at bedtime	Frequency
Qhs	nightly at bedtime	Frequency	Never writeuse “QHS or qhs for bedtime”
Qn	nightly or at bedtime	Frequency	Never writeuse “QHS or qhs for bedtime”
QAM	every morning	Frequency
PRN	as needed	Frequency
STAT	immediately	Frequency
AC	before meals	Timing
PC	after meals	Timing
HS	at bedtime	Timing
TIW	three times a week	Frequency	Never writeuse “3 times weekly”
PO	by mouth	Route
SL	sublingual (under the tongue)	Route
IM	intramuscular	Route
IV	intravenous	Route
IVP	IV push	Route
IVPB	IV piggyback	Route
SubQ	subcutaneous	Route
SC	subcutaneous	Route	Never writeuse “SUBQ or subcutaneous”
SQ	subcutaneous	Route	Never writeuse “SUBQ or subcutaneous”
PR	rectally	Route
PV	vaginally	Route
TOP	topically	Route
INH	inhalation	Route
NPO	nothing by mouth	Instructions
per os	by mouth	Route	Never writeuse “PO or 'by mouth'”
AD	right ear	Route	Never writeuse “right ear”
AS	left ear	Route	Never writeuse “left ear”
AU	each ear	Route	Never writeuse “each ear”
OD	right eye	Route	Never writeuse “right eye”
OS	left eye	Route	Never writeuse “left eye”
OU	each eye	Route	Never writeuse “each eye”
tab	tablet	Dosage form
cap	capsule	Dosage form
susp	suspension	Dosage form
sol	solution	Dosage form
supp	suppository	Dosage form
ung	ointment	Dosage form
gtt	drop	Dosage form
MDI	metered-dose inhaler	Dosage form
mL	milliliter	Measurement
cc	cubic centimeter (= 1 mL)	Measurement	Never writeuse “mL”
L	liter	Measurement
mg	milligram	Measurement
g	gram	Measurement
mcg	microgram	Measurement
µg	microgram	Measurement	Never writeuse “mcg”
kg	kilogram	Measurement
mEq	milliequivalent	Measurement
gr	grain (1 gr = 65 mg)	Measurement	Never writeuse “the metric system (e.g., mcg, g)”
tsp	teaspoon (5 mL)	Measurement	Never writeuse “the metric system (e.g., mL)”
tbsp	tablespoon (15 mL)	Measurement	Never writeuse “the metric system (e.g., mL)”
fl oz	fluid ounce (30 mL)	Measurement
U	unit	Measurement	Never writeuse “unit”
IU	international unit	Measurement	Never writeuse “unit”
AAA	apply to affected area	Instructions
SS	one half (also read as sliding scale — context decides)	Instructions	Never writeuse “one-half or sliding scale, written out”
UD	as directed	Instructions	Never writeuse “as directed”
DAW	dispense as written	Instructions
NR	no refills	Instructions
qs	a sufficient quantity	Instructions
qs ad	add a sufficient quantity to make	Instructions
aa	of each	Instructions
disp	dispense	Instructions
sig	directions (write on label)	Instructions
MS	morphine sulfate	Instructions	Never writeuse “morphine sulfate”
MSO4	morphine sulfate	Instructions	Never writeuse “morphine sulfate”
MgSO4	magnesium sulfate	Instructions	Never writeuse “magnesium sulfate”

The Never write rows, explained

26 codes in this table sit on the ISMP List of Error-Prone Abbreviations — shorthand with a documented record of causing medication errors. QD misread as QID quadruples a dose; U misread as a zero makes 4 units 40; AD/AS/AU and OD/OS/OU swap ears and eyes.

The working rule: recognize, never write. You’ll still see them on older prescriptions and on the exam, so the table keeps them searchable — each with ISMP’s preferred replacement. In any system you type into, use the written-out form.

Cheat sheets — free, no email

The full table as a printable PDF, in two versions: the shaded original, and an ink-saver with no fills for the pharmacy break-room printer.

Download the cheat sheet Ink-saver version

Can you decode these? The exam thinks so

PTCE questions rarely ask “what does BID mean” — they hand you a sig and make the translation step one of a calculation. Reveal each answer to check yourself.

Rx: 1 tab PO BID × 10 days— reveal

Take 1 tablet by mouth twice daily for 10 days.

2 tablets/day × 10 days = 20 tablets dispensed.

Rx: 2 gtt AU TID— reveal

Instill 2 drops into each ear three times daily.

4 drops/dose × 3 doses = 12 drops/day (AU = both ears — ISMP flags it; expect it written out).

Rx: 1 cap PO QID ac & HS— reveal

Take 1 capsule by mouth four times daily, before meals and at bedtime.

4 capsules/day — a 30-day supply is 120 capsules.

Drill sig codes in the Order Entry quiz Days-supply calculator

Common questions

What are sig codes in pharmacy?

Sig codes are the shorthand prescribers write on prescriptions to say how a medication is taken — “sig” from the Latin signetur, “let it be labeled.” Technicians translate them into the plain-English directions printed on the label: 1 tab PO BID becomes “take 1 tablet by mouth twice daily.”

What does AAA mean in a sig code?

Apply to affected area — an instruction code on topical prescriptions. It tells the patient to apply the cream, ointment, or solution to the area being treated rather than a fixed site. (In other medical contexts AAA can mean an aneurysm — on a prescription sig, it’s the topical instruction.)

What does qd mean in pharmacy?

Once daily — but it’s on the ISMP error-prone list because handwritten QD is easily misread as QID (four times daily) or QOD (every other day). You must recognize it on old prescriptions and the exam; in practice, write “daily” instead.

What does SS mean in a sig code?

One half — and in insulin contexts, sliding scale; the surrounding order decides. That double reading is exactly why ISMP flags it: write “one-half” or “sliding scale” out in full. Exam questions may still show it, so recognize both meanings.

What sig codes are on the PTCB exam?

Sig codes live in knowledge area 4.1 of the 2026 outline — Order Entry & Processing, 22.5% of the exam (≈18 scored questions). Expect them inside calculations: decoding a sig into doses per day is step one of most days-supply and quantity problems, which is why the Order Entry quiz drills them together.

Sources

PTCB PTCE Content Outline (area 4.1 names sig codes explicitly)checked 2026-08-03