List of Looks-alike and Sounds-alike Drugs

12 Pages·2008·0.07 MB·English

National Patient Safety Goal: Identify and, at a minimum, annually review a list of look-alike/sound-alike drugs
used in the organization, and take action to prevent errors involving the interchange of these drugs.

2006 – 2008†

Confusing drug names is a common system failure. Unfortunately, many drug names can look or sound like other drug names, which may lead to potentially
harmful medication errors. Increasingly, pharmaceutical manufacturers and regulatory authorities are taking measures to determine if there are
unacceptable similarities between proposed names and products on the market. But factors such as poor handwriting or poorly communicated oral
prescriptions can exacerbate the problem. In 2001, The Joint Commission published a Sentinel Event Alert on look-alike and sound-alike drug names. This
NPSG recognizes that health care practitioners and organizations need to be aware of the role drug names play in medication safety as well as system
changes that can be made to prevent errors.

Tables I and II below provide lists of the most problematic look-alike and sound-alike drug names for specific health care settings.* Examples of potential
errors and safety strategies specific to each of the problem drug names are provided, when applicable. Table III provides a list of other look-alike or sound-
alike drug names that were rated or suggested by experts. General safety strategies to help manage all sound-alike and look-alike drug names are listed
below the Tables, and should also be considered for implementation with each of the problematic names.

An organization’s list of look-alike/sound-alike drugs must contain a minimum of 10 drug combinations. At least five of these combinations must be selected
from Table I or from Table II, as appropriate to the type of organization. An additional five combinations must be selected from any of the Tables I, II and/or
III. This list is revised as necessary and most recent additions appear in italics. Organizations should reassess previous choices in light of new information,
including the revised list, and selection of replacement or additional pairs as indicated by the results of that assessment.

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Table I: FOR CRITICAL ACCESS HOSPITAL, HOSPITAL, OFFICE-BASED SURGERY
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Potential Problematic Drug Brand Name(s) Potential Errors and Consequences Specific Safety Strategies**
Names (UPPERCASE) & Generic
(lowercase)

1. Concentrated liquid Concentrated: Concentrated forms of oral morphine Dispense concentrated oral morphine
morphine products vs. ROXANOL solution (20 mg/mL) have often been solutions only when ordered for a specific
conventional liquid confused with the conventional patient (not as unit stock). Segregate the
morphine concentrations. morphine oral liquid concentrations (listed as 10 mg/ 5 mL or concentrated solution from the other
(conventional concentration) 20 mg/5 mL), leading to serious errors. concentrations wherever it is stored.
Accidental selection of the wrong Purchase and dispense concentrated
concentration, and prescribing/labeling solutions in dropper bottles (available from
the product by volume, not milligrams, at least two manufacturers) to help prevent
contributes to these errors, some of which dose measurement errors and differentiate
have been fatal. For example, “10 mg” the concentrated product from the
has been confused with “10 mL.” If conventional products. Verify that patients
concentrated product is used, this and caregivers understand how to measure
L represents a 20-fold overdose. the proper dose for self-administration at
as home. For inpatients, dispense
t U concentrated solutions in unit-doses.
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2. ephedrine and ADRENALIN The names of these two medications look See general recommendations below.
epinephrine (epinephrine) very similar, and their clinical uses make
storage near each other likely, especially
in obstetrical areas. Both products are
ephedrine available in similar packaging (1 mL
amber ampuls and vials).

3. hydromorphone injection DILAUDID Some health care providers have Stock specific strengths for each product
and morphine injection (hydromorphone) mistakenly believed that hydromorphone that are dissimilar. For example, stock units
is the generic equivalent of morphine. with hydromorphone 1 mg unit dose
ASTRAMOPRH, However, these products are not cartridges, and morphine in 2 mg unit dose
DURAMORPH, interchangeable. Fatal errors have cartridges. Ensure that health care providers
INFUMORPH occurred when hydromorphone was are aware that these two products are not
(morphine) confused with morphine. Based on interchangeable.
equianalgesic dose conversion, this may
represent significant overdose, leading to
serious adverse events. Storage of the
two medications in close proximity to one
another and in similar concentrations may
contribute to such errors. Confusion has
resulted in episodes of respiratory arrest
due to potency differences between these
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4. hydroxyzine and VISTARIL, ATARAX Because the first four letters of their Change appearance of look-alike product
hydralazine (hydroxyzine) names are identical, they are frequently names on computer screens, pharmacy and
stored next to one another on pharmacy nursing unit shelf labels and bins (including
shelves and automated dispensing automated dispensing cabinets), pharmacy
cabinets and listed adjacently on product labels, and medication
computer screens. Their similar dosage administration records. Differentiate drug
strengths (10, 25, 50 and 100 mg) and names by using boldface, color, and/or “tall
tablet dosage forms also contribute to man” letters, to help emphasize the letter
confusion. Confusion between the characters in each name that are unique to
antihistamine (hydroxyzine) and the that name (e.g., hydrOXYzine,
antihypertensive agent (hydralazine) hydrALAzine). Choose generic
could lead to serious adverse drug manufacturers whose products exhibit clear
events. labeling with “tall man” characters.

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5. Insulin products HUMULIN (human insulin Similar names, strengths and Limit the use of insulin analog 70/30
products) concentration ratios of some products mixtures to just a single product. Limit the
Humalog and Humulin HUMALOG (insulin lispro) (e.g. 70/30) have contributed to variety of insulin products stored in patient
Novolog and Novolin medication errors. Mix-ups have also care units, and remove patient-specific
Humulin and Novolin NOVOLIN (human insulin occurred between the 100 unit/mL and insulin vials from stock upon discharged.
Humalog and Novolog products) 500 units/mL insulin concentrations. For drug selection screens, emphasize the
Novolin 70/30 and NOVOLOG (human insulin word “mixture” or “mix” along with the name
Novolog Mix 70/30 aspart) of the insulin product mixtures. Consider
auxiliary labels for newer products to
NOVOLIN 70/30 (70% differentiate them from the established
isophane insulin [NPH] and products. Also apply bold labels on atypical
30% insulin injection insulin concentrations.
[regular])
NOVOLOG MIX 70/30 (70%
insulin aspart protamine
suspension and 30% insulin
aspart)

6. Lipid-based daunorubicin Lipid-based: Many drugs now come in liposomal Staff involved in handling these products
and doxorubicin products formulations indicated for special patient should be aware of the differences between
vs. conventional forms of DOXIL populations. Confusion may occur conventional and lipid-based formulations of
8 daunorubicin and (doxorubicin liposomal) between the liposomal and the these drugs. Encourage staff to refer to the
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5 doxorubicin conventional formulation because of lipid-based products by their brand names
DAUNOXOME name similarity. The products are not and not just their generic names. Stop and
(daunorubicin citrate interchangeable. Lipid-based formulation verify that the correct drug is being used if
liposomal) dosing guidelines differ significantly from staff, patients or family members notice a
conventional dosing. For example, a change in the solution’s appearance from
standard dose of doxorubicin liposomal is previous infusions. Lipid-based products
Conventional: 20 mg/m2 given at 21-day intervals, may be seen as cloudy rather than a clear
compared to doses of 50 to 75 mg/m2 solution. Storage of lipid-based products in
CERUBIDINE every 21 days for conventional drug. patient care areas and automated
(daunorubicin, Doses of liposomal daunorubicin are dispensing cabinets is highly discouraged.
conventional) typically 40 mg/m2 repeated every two (2) Include specific method of administration for
weeks, while doses of conventional these products.
ADRIAMYCIN, RUBEX daunorubicin vary greatly and may be
(doxorubicin, conventional) administered more frequently. Accidental
administration of the liposomal form
instead of the conventional form has
resulted in severe side effects and death.

L 7. Lipid-based amphotericin Lipid-based: Many drugs now come in liposomal Staff involved in handling these products
a
s products vs. conventional formulation indicated for special patient should be aware of the differences between
t U forms of amphotericin AMBISOME populations. Confusion may occur conventional and lipid-based formulations of
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(amphotericin B liposomal) between the liposomal and the these drugs. Encourage staff to refer to the
conventional formulations because of lipid-based products by their brand names
ABELCET (amphotericin B name similarity. The products are not and not just their generic names. Stop and
lipid complex) interchangeable. Lipid-based formulation verify that the correct drug is being used if
dosing guidelines differ significantly from staff, patients or family members notice a
conventional dosing. Conventional change in the solution’s appearance from
Conventional: amphotercin B desoxycholate doses previous infusions. Lipid-based products
should not exceed 1.5 mg/kg/day. Doses may be seen as cloudy rather than a clear
of the lipid-based products are higher, but solution. Storage of lipid-based products in
AMPHOCIN, FUNGIZONE vary from product to product. If patient care areas and automated
INTRAVENOUS conventional amphotericin B is given at a dispensing cabinets is highly discouraged.
(amphotericin B dose appropriate for a lipid-based To reduce potential for confusion, consider
desoxycholate) product, a severe adverse event is likely. limiting lipid-based amphotericin B products
Confusion between these products has to one specific brand.
resulted in episodes of respiratory arrest
and other dangerous, sometimes fatal
outcomes due to potency differences
between these drugs.

8. metformin and FLAGYL (metronidazole) Potentially serious mix-ups between To avoid order entry errors, program
metronidazole metronidazole and metformin have been computer order entry software to display
GLUCOPHAGE (metformin) linked to look-alike packaging (both bulk entire names of associated products
8 bottles and unit-dose packages) and whenever the MET stem is used as a
0 selection of the wrong product after mnemonic. Use tall man letters for unique
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entering MET as a mnemonic. Metformin letter characters in names. Pharmacy
is contraindicated in certain clinical should consider stocking metronidazole in
situations where use might contribute to only 250 mg tablets (metformin tablets are
lactic acidosis. Administration of not available as 250 mg tablets.) See also
intravenous iodinated contrast media the general recommendations below.
during radiologic procedures has been
associated with acute renal dysfunction.

9. OxyContin and oxycodone OXYCONTIN (oxycodone Mix-ups occur when staff confuse brand Do not store immediate release and
controlled-release) name, OxyContin, with oxycodone, or the controlled release products together. If
prescriber uses the generic name to order possible, have the pharmacy dispense oral
oxycodone (immediate the controlled release formulation without oxycodone products for individual patients.
release) specifying “controlled release.” Patient Always specify dosage form. Use available
may receive immediate release product in brand name when prescribing. Educate staff
dose appropriate for controlled release. about the potential for confusion. See
Significant overdose may occur. general recommendations below.

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10. vinblastine and vincristine VELBAN Fatal errors have occurred, often due to Install maximum dose warnings in computer
(vinblastine) name similarity, when patients were systems to alert staff to name mix-ups
erroneously given vincristine during order entry. Do not store these
ONCOVIN intravenously, but at the higher vinblastine agents near one another. Staff involved in
(vincristine) dose. A typical vincristine dose is usually handling these products should be aware of
capped at around 1.4 mg/m2 weekly. The the differences. Use brand names or brand
vinblastine dose is variable but, for most and generic names when prescribing and do
adults, the weekly dosage range is 5.5 to not use abbreviations for these drug names.
7.4 mg/m2.

* Note: The name pairs listed were selected after a review of error report descriptions received by the Institute for Safe Medication Practices, the United
States Pharmacopeia, the US Food and Drug Administration, and the Pennsylvania Patient Safety Reporting System (Pa-PSRS). Ratings based on
judgments of severity and likelihood of confusion in the clinical setting were provided by outside experts using a modified Delphi process. The list was
updated in August 2006 with deletions or additions recommended by medication safety staff at ISMP, USP and FDA and also based upon frequency of
reports and potential outcome severity. Appreciation is expressed to Medco Health Solutions for their input to the ambulatory drug portion of these listings.
The assistance of ISMP in providing potential error consequences and safety strategies for this project is also appreciated.

** These safety strategies are not inclusive of all possible strategies to reduce name-related errors. Also see General Recommendation for Preventing Drug
Name Mix-ups below.

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Table II: FOR AMBULATORY CARE, ASSISTED LIVING, BEHAVIORAL HEALTHCARE, DISEASE SPECIFIC CARE,
HOME CARE, LONG TERM CARE

Potential Problematic Drug Brand Name(s) (UPPERCASE) Potential Errors and Consequences Suggested Safety Strategies**
Names & Generic (lowercase)

1. Avandia and Coumadin AVANDIA Poorly handwritten orders for Avandia (used See general recommendations
(rosiglitazone) for type II diabetes) have been misread a below.
Coumadin (used to prevent blood clot
COUMADIN formation), leading to potentially serious
(warfarin) adverse events. Mix-ups originally occurred
due to unfamiliarity with Avandia- staff read
the order as the more familiar Coumadin.
However, mix-ups between these two
products continue to occur. Neither
medication is safe without appropriate
monitoring that is specific to the drug.
2. Celebrex and Celexa and CELEBREX Patients affected by a mix-up between these See general recommendations
Cerebyx (celecoxib) three drugs may experience a decline in below.
mental status, lack of pain or seizure
CELEXA control, or other serious adverse events
8 (citalopram hydrobromide)
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CEREBYX
(fosphenytoin)

3. clonidine and Klonopin CATAPRES The generic name for clonidine can easily See general recommendations
(clonidine) be confused as the trade or generic name below.
for clonazepam.
KLONOPIN
(clonazepam)

4. Concentrated liquid Concentrated: Concentrated forms of oral morphine Dispense concentrated oral
morphine products vs. ROXANOL solution (20 mg/mL) have often been morphine solutions only when
conventional liquid confused with the conventional ordered for a specific patient (not
morphine concentrations morphine oral liquid concentration (listed as 10 mg/5 mL or 20 as unit stock). Segregate the
(conventional concentration) mg/5 mL), leading to serious errors. concentrated solution from the
Accidental selection of the wrong other concentrations wherever it is
concentration, and prescribing/labeling the stored. Purchase and dispense
product by volume, not milligrams, concentrated solutions in dropper
L
a contributes to these errors, some of which bottles (available from at least two
s
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been confused with “10 mL.” If concentrated dose measurement errors and
product is used, this represents a 20-fold differentiate the concentrated
overdose. product from the conventional
products. Verify that patients and
caregivers understand how to
measure the proper dose for self-
administration at home. Dispense
concentrated solutions in unit-
doses if possible for residents in
long-term care facilities.

5. hydromorphone injection DILAUDID Some health care providers have mistakenly Stock specific strengths for each
and morphine injection (hydromorphone) believed that hydromorphone is the generic product that are dissimilar. For
equivalent of morphine. However, these example, stock units with
ASTRAMOPRH, products are not interchangeable. Fatal hydromorphone 1 mg unit dose
DURAMORPH, INFUMORPH errors have occurred when hydromorphone cartridges, and morphine in 2 mg
(morphine) was confused with morphine. Based on unit dose cartridges. Ensure that
equianalgesic dose conversion, this may health care providers are aware
represent significant overdose, leading to that these two products are not
serious adverse events. Storage of the two interchangeable.
medications in close proximity to one
another and in similar concentrations may
8 contribute to such errors. Confusion has
0 resulted in episodes of respiratory arrest
9
due to potency differences between these
drugs.

6. Insulin products HUMULIN (human insulin Similar names, strengths and concentration For drug selection screens,
products) ratios of some products (e.g., 70/30) have emphasize the word “mixture” or
HUMALOG (insulin contributed to medication errors. Mix-ups “mix” along with the name of the
Humalog and Humulin lispro) have also occurred between the 100 unit/mL insulin product mixtures. Consider
Novolog and Novolin and 500 units/mL insulin concentrations. auxiliary labels for newer products
Humulin and Novolin NOVOLIN (human insulin to differentiate them from the
Humalog and Novolog products) established products. Also apply
Novolin 70/30 and NOVOLOG (human insulin bold labels on atypical insulin
Novolog Mix 70/30 aspart) concentrations.

NOVOLIN 70/30 (70% isophane
insulin [NPH] and 30% insulin
injection [regular])
NOVOLOG MIX 70/30 (70%
insulin aspart protamine
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7. lorazepam and alprazolam ATIVAN (lorazepam) These benzodiazepines have different See general recommendations
potencies. A mix-up, especially in the below.
XANAX (alprazolam) elderly, would likely cause excessive
sedation and increase fall risk.

8. metformin and FLAGYL (metronidazole) Potentially serious mix-ups between To avoid order entry errors,
metronidazole metronidazole and metformin have been program computer order entry
GLUCOPHAGE (metformin) linked to look-alike packaging (both bulk software to display entire names of
bottles and unit-dose packages) and associated products whenever the
selection of the wrong product after entering MET stem is used as a mnemonic.
MET as a mnemonic. Metformin is Use tall man letters for unique letter
contraindicated in certain clinical situations characters in names. Pharmacy
where use might contribute to lactic should consider stocking
acidosis. Administration of intravenous metronidazole in only 250 mg
iodinated contrast media during radiological tablets (metformin tablets are not
procedures has been associated with acute available as 250 mg tablets.) See
renal dysfunction. also the general recommendations
below.

9. Topamax and Toprol XL TOPAMAX (topiramate) Error is likely attributable to the similarity in Separate the storage of these
TOPROL-XL (metoprolol). names with the “X” in XL of the beta- products. Use both brand and
8 blocker, Toprol XL, looking like the ending of generic names when prescribing
1 Topamax, an anticonvulsant. In addition, these medications to differentiate
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available dosage strengths (25, 50, 100, the two drug names. See general
200) are identical, adding to likelihood of recommendations below.
mix-up. Imprint on the Topamax tablet is
"TOP" on one side and 25 mg strength has
"25" on the other, risking confusion with
Toprol XL 25 mg.
Patients needing Topamax may develop
seizures and/or have adverse effects with
Toprol XL. Patients needing a beta-blocker
may have worsened disease symptoms
without treatment. These products might be
stored near one another if medications are
stocked alphabetically by brand name or
might appear near one another on computer
screens.

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10. Zyprexa and Zyrtec ZYPREXA Name similarity has resulted in frequent See general recommendations
(olanzapine) mix-ups between Zyrtec, an antihistamine, below.
and Zyprexa, an antipsychotic. Patients who
ZYRTEC receive Zyprexa in error have reported
(cetirizine) dizziness, sometimes leading to a related
injury from a fall. Patients on Zyprexa for a
mental illness have relapsed when given
Zyrtec in error.

* Note: The name pairs listed were selected after a review of error report descriptions received by the Institute for Safe Medication Practices, the United
States Pharmacopeia, the US Food and Drug Administration, and the Pennsylvania Patient Safety Reporting System (Pa-PSRS). Ratings based on
judgments of severity and likelihood of confusion in the clinical setting were provided by outside experts using a modified Delphi process. The list was
updated in August 2006 with deletions or additions recommended by medication safety staff at ISMP, USP and FDA and also based upon frequency of
reports and potential outcome severity. Appreciation is expressed to Medco Health Solutions for their input to the ambulatory drug portion of these listings.
The assistance of ISMP in providing potential error consequences and safety strategies for this project is also appreciated.

** These safety strategies are not inclusive of all possible strategies to reduce name-related errors. Also see General Recommendation for Preventing Drug
Name Mix-ups below.

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Table III: SUPPLEMENTAL LIST

Other name pairs that were rated or suggested by experts:

Acetohexamide – acetazolamide

Advicor and Advair

Amicar - Omacor

Avinza – Evista

Cardura - Coumadin

Darvocet - Percocet

Diabeta – Zebeta

Diflucan – Diprivan

Effexor XR - Effexor
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1 folic acid – leucovorin calcium (“folinic acid”)
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heparin - Hespan

hydrocodone – oxycodone

idarubicin – doxorubicin - daunorubicin

lamivudine – lamotrigine

Leukeran – leucovorin calcium

MS Contin – Oxycontin

Mucinex. - Mucomyst

opium tincture – paregoric (camphorated opium tincture)

Prilosec - Prozac
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