Look-Alike/Sound-Alike Medications

Full update May 2019

Confusion between similar drug names is an important cause of medication errors.1,2,5 Poor handwriting, similar product labeling, and unfamiliarity with drug names or new products are some of the factors that contribute to this problem.5 Some strategies pharmacies can consider to reduce drug name mix-ups include implementation of technology (e.g., bar-code scanning, computer alerts), use of auxiliary labels, use of tall man lettering, separating products on shelves, and reading back orders.2,3 Prescribers can help reduce look-alike/sound-alike errors by writing prescriptions clearly, not using abbreviations, and by including the indication for the medication on the prescription.1,2,4 Familiarizing yourself with potential problem drugs can also aid in the recognition and prevention of an error.2,5 Below is a listing of some of the more common or problematic look-alike/sound-alike drug names (brand names are italicized).

For a listing of confusing drug name pairs involved in med errors go to http://www.ismp.org/tools/confuseddrugnames.pdf. (Please note that the Joint Commission website no longer maintains a list of look-alike/sound-alike drug names. They now direct viewers to the ISMP list.) ISMP also has a list of look-alike drug names with recommended tall man lettering at https://www.ismp.org/recommendations/tall-man-letters-list.

* These two drug names are easily confused when poorly written.

Examples of Look-Alike and/or Sound-Alike Drug Names

Accutane and Accolate, Accupril
Acetazolamide and Acetaminophen
Aciphex and Accupril
Actonel and Actos
Adderall and Inderal
Advicor and Advair
Allegra and Viagra
Anzemet and Avandamet
Aricept and Aciphex
Aripiprazole and Rabeprazole
Asacol and Os-Cal
Atomoxetine and Atorvastatin
Avandia and Coumadin*
Avandia and Prandin
Avinza and Evista
Azathioprine and Azithromycin
Azilect and Aricept
Bicillin C-R and Bicillin L-A
Bisoprolol and Bisacodyl
Brintellix and Brilinta
Bupropion and Buspirone
Carafate and Cafergot
Carboplatin and Cisplatin
Cataflam and Catapres
Celebrex and Celexa, Cerebyx
Clonidine and Klonopin
Codeine and Cardene
Coumadin and Cardura
Depakote and Depakote ER
DiaBeta and Zebeta
Dexamethasone and Dexmedetomidine
Diazepam and Diltiazem, Ditropan
Diflucan and Diprivan
Dobutamine and Dopamine
Duloxetine and Paroxetine
Epinephrine and Ephedrine
Farxiga and Fetzima
Femara and Femhrt
Fluocinolone and Fluocinonide
Folic Acid and Folinic Acid
Foradil and Toradol
Glipizide and Glyburide
Haldol and Stadol
Humalog and Humulin, Humalog Mix, Novolog
Hydralazine and Hydroxyzine
Hydrocodone and Oxycodone
Invega and Intuniv
Keppra and Kaletra, Keflex
Labetalol and Lamotrigine
Lamisil and Lamictal
Lamivudine and Lamotrigine
Lanoxin and Levothyroxine
Lasix and Losec (Canada)
Lexiva and Levitra
Lithium and Ultram*
Lorazepam and Alprazolam
Lotensin and Lovastatin
Lovenox and Levoxyl
Malarone and Mefloquine
Melatonin and Mellaril
Metformin and Metronidazole
Methadone and Methylphenidate, Metolazone
Methocarbamol and Methotrexate
Morphine SO4 (MSO4) and Magnesium SO4 (MgSO4)
Mucinex and Mucomyst
Myfortic and Myrbetriq
Narcan and Norcuron
Neutra-Phos-K and K-Phos Neutral
Nicardipine and Nifedipine and Nimodipine
Nolvadex and Norvasc
Novolog and Novolin
Opium Tincture (deodorized) and Paregoric (camphorated opium tincture)
Oxybutynin and Oxycodone
OxyContin and MS Contin
OxyContin and Oxycodone
Plavix and Paxil
Plavix and Pradaxa
Prednisolone and Prednisone
Prilosec and Prozac
Prograf and Proscar, Prozac
Ranitidine and Rimantadine
Rifampin and Rifaximin
Risperdal and Ropinirole
Razadyne and Rozerem
Retrovir and Ritonavir
Rituxan and Rituxan Hycela
Singulair and Sinequan
Tacrolimus and Tamsulosin
Taxol and Taxotere
Tenex and Xanax
Tiagabine and Tizanidine
Toprol XL and Tegretol-XR, Tegretol, Topamax
TNKase and Activase
Tramadol and Trazodone
Valtrex and Valcyte
Valsartan and Verapamil
Vinblastine and Vincristine
Volumen and Voluven
Wellbutrin SR and Wellbutrin XL
Yasmin and Yaz
Zantac and Xanax, Zyrtec
Zestril and Zyprexa
Zetia and Zebeta, Zestril
Zocor and Zyrtec
Zyrtec and Zyprexa
Zyvox and Zovirax

Project Leader in preparation of this clinical resource (350531): Stacy A. Hester, R.Ph., BCPS, Associate Editor


  1. Seoane-Vazquez E, Rodriguez-Monguio R, Alqahtani S, Schiff G. Exploring the potential for using drug indications to prevent look-alike and sound-alike drug errors. Expert Opin Drug Saf 2017;16:1103-9.
  2. Billstein-Leber M, Carrillo CJD, Cassano AT, et al. ASHP guidelines on preventing medication errors in hospitals. Am J Health Syst Pharm 2018;75:1493-1517.
  3. Larmene-Beld KHM, Alting EK, Taxis K. A systematic literature review on strategies to avoid look-alike errors of labels. Eur J Clin Pharmacol 2018;74:985-93.
  4. ISMP. List of confused drug names. February 28, 2019. https://www.ismp.org/recommendations/confused-drug-names-list. (Accessed April 18, 2019).
  5. Kawano A, Li Q, Ho C. Preventable medication errors with look-alike/sound-alike drug names. Spring 2014. ISMP Canada. https://www.ismp-canada.org/download/PharmacyConnection/PC2014-02-Spring_LookalikeSoundalike.pdf. (Accessed April 18, 2019).

Cite this document as follows: Clinical Resource, Look-Alike/Sound-Alike Medications. Pharmacist’s Letter/Prescriber’s Letter. May 2019.

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