Tall man lettering (TML) is a technique that uses uppercase lettering to help differentiate look-alike drug names.  Starting on the left side of a drug name, TML highlights the differences between similar drug names by capitalizing dissimilar letters (e.g., vinBLAStine versus vinCRIStine and CISplatin versus CARBOplatin).  TML can be used along with color or bolding to draw attention to the dissimilarities between look-alike drug names, and alert healthcare providers that the drug name can be confused with another drug name. 

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Also see: ISMP List of Additional Drug Names with Tall Man Letters

FDA-Approved List of Generic Drug Names with Tall Man Letters

Drug Name With Tall Man Letters Confused With
acetaZOLAMIDE acetoHEXAMIDE
acetoHEXAMIDE acetaZOLAMIDE
buPROPion busPIRone
busPIRone buPROPion
chlorproMAZINE chlorproPAMIDE
chlorproPAMIDE chlorproMAZINE
clomiPHENE clomiPRAMINE
clomiPRAMINE clomiPHENE
cycloSERINE cycloSPORINE
cycloSPORINE cycloSERINE
DAUNOrubicin DOXOrubicin
dimenhyDRINATE diphenhydrAMINE
diphenhydrAMINE dimenhyDRINATE
DOBUTamine DOPamine
DOPamine DOBUTamine
DOXOrubicin DAUNOrubicin
glipiZIDE glyBURIDE
glyBURIDE glipiZIDE
hydrALAZINE hydrOXYzine – HYDROmorphone
HYDROmorphone hydrOXYzine — hydrALAZINE
hydrOXYzine hydrALAZINEHYDROmorphone
medroxyPROGESTERone methylPREDNISolone - methylTESTOSTERone
methylPREDNISolone medroxyPROGESTERone - methylTESTOSTERone
methylTESTOSTERone medroxyPROGESTERone - methylPREDNISolone
mitoXANTRONE Not specified
niCARdipine NIFEdipine
NIFEdipine niCARdipine
prednisoLONE predniSONE
predniSONE prednisoLONE
risperiDONE rOPINIRole
rOPINIRole risperiDONE
sulfADIAZINE sulfiSOXAZOLE
sulfiSOXAZOLE sulfADIAZINE
TOLAZamide TOLBUTamide
TOLBUTamide TOLAZamide
vinBLAStine vinCRIStine
vinCRIStine vinBLAStine

*Brand names always start with an uppercase letter. Some brand names incorporate tall man letters in initial characters and may not be readily recognized as brand names. An asterisk follows all brand names on the ISMP list.