Do Not Use

Intended Meaning

Potential Misinterpretation

Use Instead

Error Prone Abbreviations

μg^¥

microgram

milligram, resulting in a 1,000-fold overdose

mcg or micrograms

BT

bedtime

b.i.d. (twice daily)

bedtime

cc^¥

cubic centimeters

U or u (units)

mL or milliliters

D/C

discontinue or discharge

D/C followed by a list of medications could denote a list of medications patient should take upon discharge, or a list of medications patient should stop taking

discontinue or discharge

IJ

injection

IV (intravenous) or intrajugular

injection

HS

half-strength

at bedtime

half-strength

hs

at bedtime or hour of sleep

half-strength

bedtime

IU*

International Unit

IV (intravenous) or 10 (ten)

International Unit

MS*

morphine sulfate or magnesium sulfate

each other

morphine sulfate or magnesium sulfate

MSO₄ and MgSO₄*

morphine sulfate and magnesium sulfate

each other

morphine sulfate or magnesium sulfate

OD or o.d.

once daily

right eye (OD, oculus dexter), so that oral liquid medications may be administered to the eye

daily

Per os

orally, by mouth

left eye (OS, oculus sinister), so that oral liquid medications may be administered to the eye

PO, orally or by mouth

QD, Q.D., qd or q.d.*

every day

q.o.d (every other day); or q.i.d (four times daily), especially if period after the “q” or tail of the “q” is misread as an “i”

daily

qhs

at bedtime

qhr (every hour)

at bedtime

qn

nightly

qh (every hour)

nightly

QOD, Q.O.D., qod or q.o.d.*

every other day

q.d. (daily); or q.i.d. (four times daily), especially if the period after the “q” or the “o” is poorly written

every other day

q1d

daily

q.i.d (four times daily)

daily

q6PM, etc.

every day at 6 PM

every 6 hours

6 PM daily or 6 PM nightly

SC, SQ, sub q

subcutaneous

SC misinterpreted as SL (sublingual); SQ misinterpreted as 5 every; “q” in sub q misinterpreted as every

subcut or subcutaneously

TIW, T.I.W., tiw or t.i.w.

three times a week

3 times daily or twice a week

3 times weekly

U or u*

unit

0 (zero) or 4 (four), resulting in a 10-fold or greater overdose; cc, resulting in dose being given in volume instead of units

unit

1/d

one daily

t.i.d. (three times daily)

1 daily

Error Prone Dose Expressions

No leading zero before a decimal dose (e.g., .3 mg)*

0.3 mg

3 mg if decimal point is not seen

Use zero before a decimal point when dose is less than 1 whole dose

Trailing zero after decimal point (e.g., 5.0 mg)*

5 mg

50 mg if decimal point is not seen

Do not use trailing zeros for whole number doses

Drug name and dose written together without adequate space in between (especially for drug names ending with “L” e.g., benadryl50 mg)

Benadryl 50 mg

Benadryl 150 mg

Ensure adequate space between drug name and dose

Numerical dose and unit of measure written together without adequate space in between (e.g., 10mg, 100mL)

10 mg

100 mL

“m” is sometimes misinterpreted as one or two zeros, causing a 10- to 100-fold overdose

Ensure adequate space between dose and unit of measure

Large doses without properly inserted commas (e.g., 100000 units, 1000000 units)

100,000 units

1,000,000 unites

100000 has been misinterpreted as 10,000 or 1,000,000; 1000000 has been misinterpreted as 100,000

Use commas for dosing units at or above 1,000, or use words such as 1 “million” or 100 “thousand”

Error Prone Symbols

Apothecary units^¥

Unfamiliar to many practitioners and may be confused with metric units

metric units

>, <^¥

greater than, less than

each other; > misinterpreted as 7 (seven); < misinterpreted as letter L; <10 misinterpreted as 40

greater than or less than

@^¥

at

2 (two)

at

&

and

2 (two)

and

+

plus or and

4 (four)

and or plus

^o

hour

zero (e.g., q6^o read as q 60)

hr, h or hour

"

second

cc

seconds

/ (slash mark)

per

1 (one)

“per” to separate doses

x2d

for two days or for two doses

each other

for 2 days or for 2 doses

↑

increase

1 (one) or letter T

increase

↓

decrease

1 (one)

decrease

M

million or thousand

each other

million or thousand

K

thousand, vitamin K or potassium

each other

thousand, vitamin K or potassium

Error Prone Drug Name Abbreviations^¥ and Drug Stems

Misinterpreted due to similar abbreviations or stems for multiple drugs

Use drug names in full

DCN

doxycycline

Darvocet-N 100

doxycycline

DPH

diphenhydramine

phenytoin, formerly called diphenylhydantoin

diphenhydramine

HCT

hydrocortisone

hydrochlorothiazide

hydrocortisone

HCTZ

hydrochlorothiazide

hydrocortisone

hydrochlorothiazide

MTX

methotrexate

mitoxantrone, Mustargen

methotrexate

TAC

triamcinolone

tetracaine, adrenalin, cocaine

triamcinolone

T3

Tylenol with codeine no. 3

liothyronine

Tylenol with codeine no. 3

Norflox

stem for norfloxacin

Norflex

norfloxacin

IV Vanc

stem for intravenous vancomycin

Invanz

IV vancomycin