PTCB Quiz Prep

Look-Alike Sound-Alike (LASA) Drug Practice Questions

Updated · aligned to the 2026 PTCE outline

Confused drug-name pairs, tall man lettering, and the shelf and screen strategies that keep them apart.

16 questionsAnswers includedUntimedEvery answer cited100% free

Key takeaways

  • Tall man lettering capitalizes the distinguishing letters, as in hydrOXYzine versus hydrALAZINE.
  • ISMP and FDA both publish confused drug name lists, and ISMP maintains the tall man lettering standard.
  • Physical separation on the shelf and alerts in the dispensing software are the other standard controls.
  • Reading back and spelling out names on verbal orders catches sound-alike errors at intake.

Look-alike sound-alike pairs are drug names close enough in spelling or pronunciation to be swapped without anyone noticing. hydrOXYzine and hydrALAZINE, predniSONE and prednisoLONE, DOBUTamine and DOPamine. The consequences range from nothing to fatal, which is why the exam treats them as a safety topic rather than a memorization one.

Tall man lettering is the main countermeasure: capitalizing the letters that differ so the eye catches the difference. These questions cover both the pairs and the systems.

Want the same material as a timed, randomized run instead? Try high-alert medication practice questions, the timed Patient Safety quiz, and the Patient Safety & Quality Assurance domain guide.

All 16 lasa drugs questions and answers

Each answer is followed by an explanation and a link to the primary source it was checked against.

  1. 1. Within pharmacy practice, what does the abbreviation LASA describe?

    • A.Medications that require refrigerated storage and special labeling
    • B.Drugs with a narrow therapeutic index that require routine lab monitoring
    • C.Drug names that look alike in print or sound alike when spoken
    • D.Controlled substances with a high potential for diversion

    Answer: C. Drug names that look alike in print or sound alike when spoken

    LASA stands for look-alike/sound-alike. ISMP publishes the List of Confused Drug Names, made up of name pairs that have actually been confused in errors reported to its national reporting programs. Confusion can happen in handwriting, on computer selection screens, or in spoken orders.

    Source: online.ecri.org

  2. 2. According to the ISMP List of Confused Drug Names, the antihistamine hydrOXYzine is commonly confused with which medication?

    • A.hydrALAZINE
    • B.hydrocortisone
    • C.Hyzaar
    • D.Hycamtin

    Answer: A. hydrALAZINE

    HydrOXYzine and the blood pressure medication hydrALAZINE are a documented pair on ISMP's confused drug names list. Tall man letters capitalize the differing middle letters to help staff tell them apart. A mix-up can cause unexpected sedation or leave hypertension untreated.

    Source: online.ecri.org

  3. 3. A prescriber sends an e-prescription for traZODone 50 mg at bedtime and adds the note 'for insomnia.' According to ISMP, how does including the purpose of a medication help prevent errors?

    • A.It allows the technician to substitute a therapeutically equivalent product without approval
    • B.It lets the pharmacy bill the insurer at a higher reimbursement rate
    • C.It removes the need for barcode verification during filling
    • D.It helps staff distinguish the intended drug from look-alike or sound-alike names such as traMADol

    Answer: D. It helps staff distinguish the intended drug from look-alike or sound-alike names such as traMADol

    ISMP lists including the purpose of the medication on prescriptions among its strategies for preventing confusion between look-alike and sound-alike names. TraZODone and traMADol are a documented LASA pair. An indication such as insomnia points staff toward the sedating antidepressant instead of the opioid analgesic.

    Source: online.ecri.org

  4. 4. A technician can only read 'Cele___ 20 mg daily' on a faxed order for a patient with a history of depression, so the pharmacist calls the prescriber to confirm. Which documented ISMP LASA group made this clarification essential?

    • A.Celestone, Cipro, and Cymbalta
    • B.CeleXA, CeleBREX, and Cerebyx
    • C.Cetirizine, Cardizem, and Colace
    • D.Cephalexin, Cozaar, and Cortef

    Answer: B. CeleXA, CeleBREX, and Cerebyx

    CeleXA (citalopram), CeleBREX (celecoxib), and Cerebyx (fosphenytoin) form a well-known confusion group on the ISMP List of Confused Drug Names. An antidepressant, an anti-inflammatory, and an anticonvulsant could each plausibly be dosed at 20 mg daily. Verifying with the prescriber is the only safe way to resolve an illegible name in this group.

    Source: online.ecri.org

  5. 5. A hospital technician restocking insulin notices NovoLOG Mix 70/30 stored directly beside NovoLIN 70/30. Based on the ISMP List of Confused Drug Names, why does this arrangement create risk?

    • A.Insulin pens and vials may never share the same refrigerator shelf
    • B.NovoLOG and NovoLIN are a documented look-alike/sound-alike insulin pair
    • C.The 70/30 designation is prohibited on hospital insulin labels
    • D.Premixed insulins must always be stored at room temperature

    Answer: B. NovoLOG and NovoLIN are a documented look-alike/sound-alike insulin pair

    NovoLIN 70/30 and NovoLOG Mix 70/30 appear as a confused name pair on the ISMP list, along with NovoLOG versus NovoLIN and HumaLOG versus HumuLIN. The names and percentages look nearly identical at a glance, but the products contain different insulins with different onset times. Separating storage and flagging the names helps prevent a wrong-insulin selection.

    Source: online.ecri.org

  6. 6. Per the ISMP List of Confused Drug Names, ZyPREXA (olanzapine) has been confused with which commonly stocked allergy medication?

    • A.Allegra (fexofenadine)
    • B.Claritin (loratadine)
    • C.Xyzal (levocetirizine)
    • D.ZyrTEC (cetirizine)

    Answer: D. ZyrTEC (cetirizine)

    ZyPREXA, an antipsychotic, and ZyrTEC, an antihistamine, are a documented pair on the ISMP confused drug names list. Dispensing the antipsychotic to an allergy patient, or the reverse, has serious clinical consequences. ZyPREXA is also listed as confused with CeleXA and Zestril.

    Source: online.ecri.org

  7. 7. While filling a prescription for metFORMIN 500 mg, a technician accidentally pulls a stock bottle of metroNIDAZOLE 500 mg from a nearby shelf. Which safeguard is specifically designed to catch this wrong-drug error during the filling step?

    • A.Scanning the stock bottle barcode so the system verifies the NDC against the entered prescription
    • B.Counting the tablets twice on a dedicated counting tray
    • C.Rechecking the days' supply calculation printed on the label
    • D.Asking the patient to confirm their date of birth at pickup

    Answer: A. Scanning the stock bottle barcode so the system verifies the NDC against the entered prescription

    MetFORMIN and metroNIDAZOLE are a documented ISMP LASA pair with matching 500 mg strengths, which makes shelf mix-ups easy. The PTCE content outline lists barcode usage among core error prevention strategies. A barcode scan compares the NDC of the product actually in hand against the drug entered on the order, catching the error before verification.

    Source: ptcb.org

  8. 8. Which drug appears on the ISMP List of Confused Drug Names as commonly confused with busPIRone?

    • A.buprenorphine
    • B.butalbital
    • C.buPROPion
    • D.bumetanide

    Answer: C. buPROPion

    BusPIRone, an anxiolytic, and buPROPion, an antidepressant and smoking cessation aid, are a documented LASA pair. Both the FDA and ISMP recommend tall man lettering to emphasize the differing letters. The other options are not listed as confused with busPIRone.

    Source: online.ecri.org

  9. 9. Which ISMP LASA pair is especially dangerous in a community pharmacy because both members also belong to a class on ISMP's community/ambulatory high-alert list (oral hypoglycemic agents)?

    • A.Paxil and Plavix
    • B.Flonase and Flovent
    • C.Zantac and Xanax
    • D.glipiZIDE and glyBURIDE

    Answer: D. glipiZIDE and glyBURIDE

    GlipiZIDE and glyBURIDE are a documented confused name pair, and oral hypoglycemic agents appear as a class on the ISMP List of High-Alert Medications in Community/Ambulatory Healthcare. A mix-up risks serious hypoglycemia because the two sulfonylureas differ in potency and duration. The other pairs are LASA drugs but are not both community high-alert agents.

    Source: ismp.org

  10. 10. A labor-and-delivery order for oxytocin is misread and OxyCONTIN is nearly dispensed. According to the ISMP List of Confused Drug Names, which additional long-acting opioid is also paired with OxyCONTIN?

    • A.MS Contin
    • B.Motrin
    • C.Methergine
    • D.Mucomyst

    Answer: A. MS Contin

    The ISMP list pairs OxyCONTIN with oxytocin, MS Contin, oxyCODONE, oxyBUTYnin, and oxyMORphone. MS Contin (morphine) and OxyCONTIN (oxycodone) are both long-acting opioids whose names share the Contin suffix. Confusing any of these products can cause severe patient harm.

    Source: online.ecri.org

  11. 11. What is the primary purpose of tall man lettering, as in vinBLAStine and vinCRIStine?

    • A.To indicate that a drug is available only under its brand name
    • B.To capitalize the dissimilar letters so look-alike drug names are easier to tell apart
    • C.To mark medications that must be stored in the refrigerator
    • D.To show which syllable is stressed when pronouncing the name

    Answer: B. To capitalize the dissimilar letters so look-alike drug names are easier to tell apart

    Tall man lettering uses uppercase letters, starting from the left side of the name, to highlight the parts of similar drug names that differ. The FDA notes it can be combined with bolding or color to further draw attention. It alerts staff that a name can be confused with another product.

    Source: fda.gov

  12. 12. Per the FDA Name Differentiation Project list, which is the recommended tall man presentation for the corticosteroid prednisone?

    • A.PREDnisone
    • B.predNISone
    • C.predniSONE
    • D.prednisONE

    Answer: C. predniSONE

    The FDA list pairs predniSONE with prednisoLONE, capitalizing the endings where the two names differ. The uppercase SONE versus LONE distinction is the key visual cue. The two corticosteroids have different potencies, so a mix-up is clinically significant.

    Source: fda.gov

  13. 13. When the FDA determines that tall man lettering should address confusion between an established drug name pair, how is the change implemented?

    • A.FDA requests that the manufacturer voluntarily revise its labels and labeling to use tall man letters
    • B.FDA suspends the drug's approval until a new name is assigned
    • C.FDA requires the USAN Council to issue a completely new generic name
    • D.FDA adds a boxed warning describing the name confusion

    Answer: A. FDA requests that the manufacturer voluntarily revise its labels and labeling to use tall man letters

    The FDA started its Name Differentiation Project in 2001 to evaluate postmarketing reports of name pair confusion. When tall man lettering is deemed appropriate, the agency asks the manufacturer to voluntarily revise labels and labeling, then updates its published list. FDA may also consider labeling revisions and safety communications.

    Source: fda.gov

  14. 14. Under ISMP's CD3 rule for constructing tall man letters, where does capitalization begin?

    • A.Capitalize the first three letters of every look-alike drug name
    • B.Capitalize only the final syllable of the longer drug name
    • C.Capitalize alternating letters throughout the entire name
    • D.Working from the left of the name, capitalize once two or more dissimilar letters are encountered

    Answer: D. Working from the left of the name, capitalize once two or more dissimilar letters are encountered

    The CD3 methodology works from the left, capitalizing to the right once two or more dissimilar letters appear, then works from the right to return two or more shared letters to lowercase. When no common letters exist on the right side, only the central part of the word is capitalized. ISMP uses this tested rule to standardize its recommendations.

    Source: online.ecri.org

  15. 15. A technician is printing warning labels for the chemotherapy storage shelf. Which pair matches the FDA's recommended tall man lettering for the two look-alike platinum agents?

    • A.CISPLATin and CARBOPLATin
    • B.cisPLATIN and carboPLATIN
    • C.CISplatin and CARBOplatin
    • D.CisplatIN and CarboplatIN

    Answer: C. CISplatin and CARBOplatin

    The FDA Name Differentiation Project lists CISplatin and CARBOplatin, capitalizing the differing left-side letters. Dosing confusion between these chemotherapy agents has caused fatal overdoses, since carboplatin doses are numerically much larger than cisplatin doses. Correct tall man rendering on shelf labels reinforces the difference.

    Source: fda.gov

  16. 16. Which statement best reflects ISMP's current position on the effectiveness of tall man lettering?

    • A.Tall man lettering by itself has been proven to eliminate wrong-drug errors
    • B.The evidence is mixed, but tall man lettering is worth implementing as one of numerous strategies against name confusion
    • C.ISMP has withdrawn its tall man letters list pending further research
    • D.Tall man lettering is legally required on all generic drug labeling

    Answer: B. The evidence is mixed, but tall man lettering is worth implementing as one of numerous strategies against name confusion

    ISMP notes that studies between 2000 and 2021 generally support tall man letters for improving name perception, while some studies found conflicting or negative results, partly due to methodological limits. ISMP is participating in FDA-funded research at Northwestern University to clarify the effect. Meanwhile it considers the technique simple and worth using alongside other safeguards, not as a standalone fix.

    Source: online.ecri.org

LASA Drugs: FAQ

What does LASA stand for?

Look-alike sound-alike. It describes pairs of drug names similar enough in appearance or pronunciation that one can be selected in place of the other during prescribing, order entry or dispensing.

What is tall man lettering?

A labeling convention that capitalizes the letters distinguishing two similar drug names so the difference is visually obvious. hydrOXYzine and hydrALAZINE is a standard example. ISMP maintains the recommended list.

How do pharmacies prevent LASA errors?

Tall man lettering on labels and shelf tags, physical separation of the two products, software alerts at order entry, barcode scanning at dispensing, and reading back plus spelling out drug names on verbal orders.

Official sources checked

Every answer above was written against a primary source and verified independently. These are the 5 sources behind this set.

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