Table 1.
Number of dispensings in the database of the individual drugs involved, the eleven potential D–DIs and the calculated ratio
| Drug–drug interaction | Number of dispensings drug A × 1,000 (range) | Number of dispensings drug B × 1,000 (range) | Number of D–DIs counted (range) | Average ratio (range)a | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Drug A | Drug B | |||||||||
| 1 | Erythromycin, clarithromycin, azithromycin, roxithromycin | Digoxin | 440.8 | (0–2754) | 487.0 | (0–3064) | 3,993 | (0–41) | 1.39 | (0–18.52) |
| 2 | Itraconazole | Digoxin | 88.7 | (0–349) | 487.0 | (0–3064) | 245 | (0–7) | 0.45 | (0–21.69) |
| 3 | Ciprofloxacin | Theophylline | 105.4 | (0–769) | 100.9 | (0–756) | 944 | (0–14) | 6.39 | (0–534.38) |
| 4 | Miconazole oral gel | Acenocoumarol, fenprocoumon | 44.6 | (0–233) | 608.2 | (5–3156) | 154 | (0–3) | 0.38 | (0–21.30) |
| 5 | Erythromycin | Carbamazepine | 49.7 | (0–531) | 193.6 | (0–871) | 35 | (0–4) | 0.24 | (0–40.92) |
| 6 | Erythromycin, clarithromycin, azithromycin | Disopyramide | 426.6 | (0–2754) | 9.4 | (0–151) | 61 | (0–4) | – | |
| 7 | Erythromycin, clarithromycin | Pimozide | 274.4 | (0–2004) | 57.4 | (0–394) | 70 | (0–15) | 0.46 | (0–46.12) |
| 8 | Propranolol, oxprenolol, pindolol | beta2-mimetics, inhalation corticosteroids | 250.6 | (1–1075) | 2,546.9 | (27–10504) | 5,127 | (0–94) | 0.54 | (0–12.98) |
| 9 | Erythromycin, clarithromycin | Cisapride | 274.4 | (0–2004) | 127.5 | (0–821) | 586 | (0–11) | 1.16 | (0–40.45) |
| 10 | Itraconazole, fluconazole, ketoconazole | Cisapride | 199.9 | (0–727) | 127.5 | (0–821) | 347 | (0–12) | 0.95 | (0–57.10) |
| 11 | Acenocoumarol, fenprocoumon | Azapropazon | 608.2 | (5–3156) | 8.4 | (0–164) | 32 | (0–19) | – | |
aCalculated with Formula 1