Table 1.
Correct drug–drug interaction alert responses by combination and pharmacy type*
| Drug combinations | Correct responses all pharmacies (n=64) | Correct responses community pharmacies (n=40) | Correct responses inpatient hospital pharmacies (n=14) | Correct responses ‘other’ pharmacies (n=10) |
| N (%) | N (%) | N (%) | N (%) | |
| Clinically significant drug–drug interactions | ||||
| Carbamazepine+clarithromycin | 57/64 (89) | 37/40 (93) | 13/14 (93) | 7/10 (70) |
| Digoxin+amiodarone | 55/64 (86) | 32/40 (80) | 13/14 (93) | 10/10 (100) |
| Digoxin+clarithromycin | 56/64 (88) | 36/40 (90) | 11/14 (79) | 9/10 (90) |
| Digoxin+itraconazole | 27/60 (45) | 20/39 (51) | 4/14 (29) | 3/7 (43) |
| Nitroglycerine+sildenafil | 51/63 (81) | 32/40 (80) | 12/14 (86) | 7/9 (78) |
| Simvastatin+amiodarone | 48/64 (75) | 32/40 (80) | 7/14 (50) | 9/10 (90) |
| Simvastatin+gemfibrozil | 54/64 (84) | 35/40 (88) | 12/14 (86) | 7/10 (70) |
| Simvastatin+itraconazole | 54/60 (90) | 36/39 (92) | 12/14 (86) | 6/7 (86) |
| Warfarin+amiodarone | 55/63 (87) | 34/40 (85) | 11/13 (85) | 10/10 (100) |
| Warfarin+fluconazole | 53/64 (83) | 34/40 (85) | 12/14 (86) | 7/10 (70) |
| Warfarin+gemfibrozil | 51/64 (80) | 35/40 (88) | 10/14 (71) | 6/10 (60) |
| Warfarin+naproxen | 45/64 (70) | 32/40 (80) | 4/14 (29) | 9/10 (90) |
| Warfarin+sulfamethoxazole/trimethoprim | 48/64 (75) | 27/40 (68) | 12/14 (86) | 9/10 (90) |
| Non-interacting pairs | ||||
| Acetaminophen/codeine+amoxicillin | 64/64 (100) | 40/40 (100) | 14/14 (100) | 10/10 (100) |
| Carbamazepine+erythromycin ophthalmic | 57/64 (89) | 34/40 (85) | 13/14 (93) | 10/10 (100) |
| Metformin+erythromycin ophthalmic | 64/64 (100) | 40/40 (100) | 14/14 (100) | 10/10 (100) |
| Digoxin+sildenafil | 63/63 (100) | 40/40 (100) | 14/14 (100) | 9/9 (100) |
| Warfarin+digoxin | 64/64 (100) | 40/40 (100) | 14/14 (100) | 10/10 (100) |
| Warfarin+pravastatin | 62/62 (100) | 40/40 (100) | 14/14 (100) | 8/8 (100) |
*
Four of the surveyed pharmacies (6%) were unable to enter at least one of the medications in the fictitious profile; either the medication was not on the formulary, or it was unavailable in their drug database. Consequently, the results for these pharmacies were calculated based on the drug pairs that were successfully entered into their respective systems.