Table 3.
Most frequently occurring major, moderate, and contraindicated interactions, their levels, and potential adverse outcomes
| Interaction | Frequency | Percentage | Severity | Evidence | Onset | Potential adverse outcomes |
|---|---|---|---|---|---|---|
| Ferrous sulfate + omeprazole | 34 | 5.8 | Moderate | Good | Rapid | Reduced non-heme iron bioavailability |
| Calcium/vitamin D + ciprofloxacin | 28 | 4.8 | Moderate | Good | Rapid | Decreased ciprofloxacin efficacy |
| Captopril + furosemide | 24 | 4.1 | Moderate | Good | Rapid | Postural hypotension |
| Calcium gluconate + ceftriaxone | 21 | 3.6 | Contraindicated | Good | Not specified | Formation of ceftriaxone–calcium precipitates |
| Ciprofloxacin + ferrous sulfate | 17 | 2.9 | Moderate | Fair | Rapid | Decreased ciprofloxacin effectiveness |
| Amlodipine + atenolol | 13 | 2.2 | Moderate | Good | Rapid | Hypotension and/or bradycardia |
| Amlodipine + ciprofloxacin | 12 | 2.0 | Moderate | Fair | Not specified | Increased amlodipine exposure |
| Amlodipine + prednisolone | 11 | 1.9 | Moderate | Fair | Not specified | Reduced amlodipine efficacy |
| Furosemide + lisinopril | 11 | 1.9 | Moderate | Good | Rapid | Postural hypotension |
| Atenolol + prazosin | 10 | 1.7 | Moderate | Good | Rapid | Exaggerated hypotensive response |
| Ciprofloxacin + metronidazole | 9 | 1.5 | Major | Fair | Not specified | Increased risk of QT-interval prolongation and arrhythmias |
| Aspirin + calcium/vitamin D | 8 | 1.4 | Moderate | Fair | Delayed | Decreased salicylate effectiveness |
| Ciprofloxacin + prednisolone | 8 | 1.4 | Moderate | Excellent | Delayed | Increased risk of tendon rupture |
| Amlodipine + carbamazepine | 6 | 1.0 | Major | Fair | Not specified | Decreased exposure of amlodipine |
| Amlodipine + aspirin | 6 | 1.0 | Moderate | Good | Delayed | Increased risk of gastrointestinal hemorrhage and/or antagonism of hypotensive effect |
| Aspirin + sodium bicarbonate | 6 | 1.0 | Moderate | Fair | Delayed | Decreased salicylate effectiveness |
| Metronidazole + moxifloxacin | 5 | 0.9 | Major | Fair | Not specified | Increased risk of QT-interval prolongation and arrhythmias |
| Aspirin + insulin human regular | 5 | 0.9 | Moderate | Fair | Not specified | Increased risk of hypoglycemia |
| Carbamazepine + omeprazole | 5 | 0.9 | Moderate | Good | Delayed | Increased risk of carbamazepine toxicity |
| Enalapril + furosemide | 5 | 0.9 | Moderate | Good | Rapid | Postural hypotension |
| Amlodipine + simvastatin | 4 | 0.7 | Major | Good | Rapid | Increased simvastatin exposure and increased risk of myopathy, including rhabdomyolysis |
| Lisinopril + spironolactone | 4 | 0.7 | Major | Good | Delayed | Hyperkalemia |
| Atorvastatin + clopidogrel | 4 | 0.7 | Moderate | Excellent | Not specified | High on-treatment platelet reactivity |
| Carbamazepine + ciprofloxacin | 4 | 0.7 | Moderate | Fair | Not specified | Increased carbamazepine exposure |
| Ferrous sulfate + moxifloxacin | 4 | 0.7 | Moderate | Good | Rapid | Decreased moxifloxacin effectiveness |
| Furosemide + insulin human regular | 4 | 0.7 | Moderate | Fair | Not specified | Increased hyperglycemia risk; increased insulin requirement |
| Calcium acetate + ceftriaxone | 3 | 0.5 | Contraindicated | Good | Not specified | Formation of ceftriaxone–calcium precipitates |