Table 1.
Clinically relevant drug–drug interactions, types, effects, and frequencies.
| Number of relevant DDIs (type D and/ or X) per patient | Number of patients (n = 297) | (%a) | |
|---|---|---|---|
| 1 | 137 | 23.1 | |
| 2 | 59 | 9.9 | |
| 3–4 | 78 | 13.2 | |
| ≥ 5 | 23 | 3.9 | |
| Patients with at least 1 type D DDI Top 10 most frequent type D interactions | Effect | n = 279 | 47 |
| Combination of drugs with CNS depressant effects (non-opioids) | Risk of CNS depressant effect | 64 | 10.8 |
| Benzodiazepines/opioids | Risk of deep sedation and respiratory depression | 35 | 5.9 |
| Amlodipine/Simvastatin | Risk of increased levels of simvastatin | 31 | 5.2 |
| Combination of high- and low-risk drugs for QT interval prolongation | Risk of QT segment prolongation | 21 | 3.5 |
| Duplication of benzodiazepines | Risk of sedation, falls and confusion | 20 | 3.4 |
| ACEI/ Allopurinol | Risk of skin reactions | 16 | 2.7 |
| Citalopram, escitalopram and cilostazol/CYP2C19 Inhibitors | Risk of QT segment prolongation | 15 | 2.5 |
| Triple whammy (ACEI or AIIRA/ diuretic/ NSAID) | Risk of renal failure | 15 | 2.5 |
| Insulins/ SGLT2 inhibitors | Risk of acidosis | 14 | 2.3 |
| Sulfonylureas/ DPP-IV Inhibitors | Risk of severe hypoglycaemia | 13 | 2.2 |
aPercentage of the total number of patients studied (n = 593). DDI: drug–drug interaction; Type D: consider therapy modification; Type X: avoid combination; CNS: central nervous system; ACEI: angiotensin-converting enzyme inhibitor; AIIRA: angiotensin II receptor antagonist; PPI: proton pump inhibitor; NSAID: non-steroidal anti-inflammatory drug.