SPECIAL ISSUE: Do not use these dangerous
abbreviations or dose designations

Abbreviation/Dose Expression

Intended Meaning

Misinterpretation

Correction

Apothecary symbols

dram
minim

Misunderstood or misread (symbol for dram misread for "3" and minim misread as "mL").

Use the metric system.

AU

aurio uterque (each ear)

Mistaken for OU (oculo uterque-each eye).

Don't use this abbreviation.

D/C

discharge
discontinue

Premature discontinuation of medications when D/C (intended to mean "discharge") has been misinterpreted as "discontinued" when followed by a list of drugs.

Use "discharge" and "discontinue."

Drug names

Use the complete spelling for drug names.

ARAºA

vidarabine

cytarabineARAºC

AZT

zidovudine
(RETROVIR)

azathioprine

CPZ

COMPAZINE
(prochlorperazine)

chlorpromazine

DPT

DEMEROL-PHENERGAN-THORAZINE

diphtheria-pertussis-tetanus (vaccine)

HCl

hydrochloric acid

potassium chloride (The "H" is misinterpreted as "K.")

HCT

hydrocortisone

hydrochlorothiazide

HCTZ

hydrochlorothiazide

hydrocortisone (seen as HCT250 mg)

MgSO4

magnesium sulfate

morphine sulfate

MSO4

morphine sulfate

magnesium sulfate

MTX

methotrexate

mitoxantrone

TAC

triamcinolone

tetracaine, ADRENALIN,cocaine

ZnSO4

zinc sulfate

morphine sulfate

Stemmed names

"Nitro" drip

nitroglycerin infusion

sodium nitroprusside infusion

"Norflox"

norfloxacin

NORFLEX

m g

microgram

Mistaken for "mg" when handwritten.

Use "mcg."

o.d. or OD

once daily

Misinterpreted as "right eye" (OD-oculus dexter)and administration of oral medications in the eye.

Use "daily."

TIW or tiw

three times a week.

Mistaken as "three times a day."

Don't use this abbreviation.

per os

orally

The "os" can be mistaken for "left eye."

Use "PO," "by mouth," or "orally."

q.d. or QD

every day

Mistaken as q.i.d., especially if the period after the "q" or the tail of the "q" is misunderstood as an "i."

Use "daily" or "every day."

qn

nightly or at bedtime

Misinterpreted as "qh" (every hour).

Use "nightly."

qhs

nightly at bedtime

Misread as every hour.

Use "nightly."

q6PM, etc.

every evening at 6 PM

Misread as every six hours.

Use 6 PM "nightly."

q.o.d. or QOD

every other day

Misinterpreted as "q.d." (daily) or "q.i.d. (four times daily) if the "o" is poorly written.

Use "every other day."

sub q

subcutaneous

The "q" has been mistaken for "every" (e.g., one heparin dose ordered "sub q 2 hours before surgery" misunderstood as every 2 hours before surgery).

Use "subcut." or write "subcutaneous."

SC

subcutaneous

Mistaken for SL (sublingual).

Use "subcut." or write "subcutaneous."

U or u

unit

Read as a zero (0) or a four (4), causing a 10‑fold overdose or greater (4U seen as "40" or 4u seen as 44").

"Unit" has no acceptable abbreviation. Use "unit."

IU

international unit

Misread as IV (intravenous).

Use "units."

cc

cubic centimeters

Misread as "U" (units).

Use "mL."

x3d

for three days

Mistaken for "three doses."

Use "for three days."

BT

bedtime

Mistaken as "BID" (twice daily).

Use "hs."

ss

sliding scale (insulin) or ½ (apothecary)

Mistaken for "55."

Spell out "sliding scale." Use "one-half" or use "½."

> and <

greater than and less than

Mistakenly used opposite of intended.

Use "greater than" or "less than."

/ (slash mark)

separates two doses or indicates "per"

Misunderstood as the number 1 ("25 unit/10 units" read as "110" units.

Do not use a slash mark to separate doses.
Use "per."

Name letters and dose numbers run together
(e.g., Inderal40 mg)

Inderal 40 mg

Misread as Inderal 140 mg.

Always use space between drug name, dose and unit of measure.

Zero after decimal point (1.0)

1 mg

Misread as 10 mg if the decimal point is not seen.

Do not use terminal zeros for doses expressed in whole numbers.

No zero before decimal dose
(.5 mg)

0.5 mg

Misread as 5 mg.

Always use zero before a decimal when the dose is less than a
whole unit.