FDA labels, quoted
Drug interactions in the labels
What FDA labels say about taking medicines together: 14,122 pairs of medicines named in each other's labels; 1,523 of the labels read on October 8, 2026 name at least one other medicine on PlainMeds. PlainMeds quotes the labels and does not grade interactions.
Which medicines do other labels name most?
| Medicine | Labels naming it |
|---|---|
| Phenytoin | 290 |
| Rifampin | 267 |
| Warfarin | 254 |
| Ketoconazole | 242 |
| Carbamazepine | 217 |
| Digoxin | 206 |
| Cyclosporine | 190 |
| Ritonavir | 183 |
| Itraconazole | 169 |
| Lithium | 150 |
| Phenobarbital | 150 |
| Erythromycin | 136 |
| Clarithromycin | 133 |
| Cimetidine | 121 |
| Quinidine | 119 |
| Methotrexate | 103 |
| Theophylline | 100 |
| Tacrolimus | 98 |
| Fluconazole | 91 |
| Verapamil | 89 |
| Midazolam | 85 |
| Voriconazole | 83 |
| Diltiazem | 82 |
| Aspirin | 80 |
| Fluoxetine | 79 |
| Nelfinavir | 79 |
| Simvastatin | 79 |
| Rifabutin | 78 |
| Amiodarone | 77 |
| Atazanavir | 75 |
| Atorvastatin | 74 |
| Paroxetine | 69 |
| Methadone | 68 |
| Omeprazole | 66 |
| Epinephrine | 65 |
| Linezolid | 65 |
| Probenecid | 63 |
| Efavirenz | 62 |
| Methylene blue | 58 |
| Propranolol | 57 |
Source: FDA drug labels (drug interactions, contraindications, boxed warnings) via openFDA