Confirmed errors, with suspected intended medication, similarity level and number of occurrences
| Similarity level | Medication ordered | Medication intended | Number of occurrences | Previously published case report |
| 10 | Cycloserine | Ciclosporin* | 9 | Yes |
| 9 | Butabarbital | Butalbital | 1 | Yes |
| 8 | Hydralazine | Hydroxyzine | 3 | Yes |
| 8 | Hydroxyzine | Hydralazine | 2 | Yes |
| 8 | Sulfadiazine | Sulfasalazine | 5 | Yes |
| 8 | Valacyclovir | Valganciclovir | 3 | Yes |
| 8 | Valganciclovir | Valacyclovir | 12 | Yes |
| 7 | Clomiphene | Clomipramine | 3 | Yes |
| 7 | Clomipramine | Clomiphene | 1 | Yes |
| 7 | Rifampin | Rifaximin | 1 | Yes |
| 6 | Cyclobenzaprine | Ciclosporin | 1 | Yes |
| 6 | Lactase | Lactulose | 2 | No |
| 6 | Methohexital* | Methotrexate* | 1 | Yes |
| 5 | Cilastatin | Cilostazol | 1 | No |
| 5 | Sumatriptan | Somatropin | 1 | No |
| 4 | Dicyclomine | Doxycycline | 1 | Yes |
| 3 | Diphenhydramine | Desipramine | 1 | No |
| 3 | Levocetirizine | Levothyroxine | 1 | No |
| 3 | Loratadine | Lovastatin | 1 | No |
| 3 | Metolazone | Metoclopramide | 1 | Yes |
| 3 | Metoprolol* | Metoclopramide | 1 | Yes |
| 3 | Nitrofurantoin | Nitroglycerin | 1 | Yes |
| 3 | Tizanidine | Ranitidine | 1 | No |
| 2 | Azathioprine | Azithromycin | 1 | Yes |
| 2 | Escitalopram | Enalapril | 2 | Yes |
| 2 | Levocarnitine | Levofloxacin | 1 | No |
| 1 | Cholestyramine | Chlorpromazine | 1 | No |
| 1 | Hydrochlorothiazide | Hydroxyzine | 1 | Yes |
| 1 | Hydroxyzine | Hydrochlorothiazide | 1 | Yes |
An asterisk indicates that the drug is on the Institute for Safe Medication Practices’ list of high-alert medications.