Why these mistakes happen
Drug names are built from shared stems, which is useful for clinicians and dangerous for everyone else. Names that begin with the same four or five letters end up adjacent in a pharmacy drawer, in a dropdown list and in handwriting. The error is rarely carelessness — it is that the first half of the two words is genuinely identical, and the eye stops reading once it recognises the beginning.
Tall Man lettering
The standard mitigation is to capitalise the part that differs, so the difference is carried by shape rather than by careful reading. Written as metFORMIN and metOPROLOL, the two stop looking alike. Hospitals and pharmacies have used this convention for years on shelf labels and infusion charts, and it works because it moves the distinguishing information to where the eye is already looking.
The chart maker on this site uses the same convention in its medicine suggestions. When you type the first few letters of a confusable name, the suggestions show the differing portion in capitals and in red, and nothing is ever filled in automatically — a suggestion only becomes text when you deliberately tap it.
Common confusable pairs
| One medicine | Often confused with |
|---|---|
| metFORMINMetformin | metOPROLOLMetoprolol |
| metFORMINMetformin | methoTREXATEMethotrexate |
| predniSOLONEPrednisolone | predniSONEPrednisone |
| clonazePAMClonazepam | cloNIDineClonidine |
| hydrOXYzineHydroxyzine | hydrALAzineHydralazine |
| amLODIPineAmlodipine | amIODAroneAmiodarone |
| glipiZIDEGlipizide | glimePIRIDEGlimepiride |
| glimePIRIDEGlimepiride | gliCLAZIDEGliclazide |
| lamoTRIgineLamotrigine | levETIRAcetamLevetiracetam |
| cefIXIMECefixime | cefUROXimeCefuroxime |
| cefUROXimeCefuroxime | cefPODOXimeCefpodoxime |
| azithroMYCINAzithromycin | erythroMYCINErythromycin |
| erythroMYCINErythromycin | clarithroMYCINClarithromycin |
| ciproFLOXacinCiprofloxacin | levoFLOXacinLevofloxacin |
| levoFLOXacinLevofloxacin | moxiFLOXacinMoxifloxacin |
| traMADolTramadol | traZODoneTrazodone |
| losARTANLosartan | olmeSARTANOlmesartan |
| olmeSARTANOlmesartan | telmiSARTANTelmisartan |
| sitaGLIPtinSitagliptin | vildaGLIPtinVildagliptin |
| dapaGLIFLOzinDapagliflozin | empaGLIFLOzinEmpagliflozin |
| chlorproMAZINEChlorpromazine | chlorproPAMIDEChlorpropamide |
Practical habits that prevent the error
- Read the whole medicine name, not just the first few letters
- Check the strength as well as the name
- Keep the printed chart beside the strips so names can be matched by sight
Read the whole name, not the first half. Check the strength as well as the name, because a wrong strength of the right medicine is also an error. Keep the printed chart and the strips together so the name on the paper can be matched against the name on the foil by sight. And when someone else collects the medicines, hand them the pocket card rather than telling them the name aloud — spoken names are where sound-alike errors happen.
A note on safety. This page is about names, not about treatment. If you think you have taken the wrong medicine, contact a doctor or pharmacist straight away rather than waiting to see what happens.
Print a chart with full, unambiguous names
Names are never abbreviated or truncated on a printed PillsChart, and confusable names are flagged as you type.
Open the chart maker