Table 4.
Adverse drug reactions by drug–drug interaction
| DDI | ADEs | ADE details and classification |
|---|---|---|
| Highest-severity alerts | ||
| Dofetilide–QT-prolonging agents | 4 | QTc prolongation |
| Severity: serious (n = 4) | ||
| Location: inpatient medicine (n = 3), ICU (n = 1) | ||
| Dofetilide–thiazide diuretics | 3 | QTc prolongation |
| Severity: serious (n = 3) | ||
| Location: outpatient clinics (n = 2), Non-ICU inpatient (n = 1) | ||
| Tizanidine–ciprofloxacin | 2 | Hypotension: BP decrease to 80/48 mm Hg in one patient and to 96/53 mm Hg in another patient with symptoms and monitoring noted |
| Severity: serious (n = 2) | ||
| Location: non-ICU inpatient (n = 2) | ||
| Additional high-priority alerts | ||
| Amiodarone–QT-prolonging agents | 7 | QTc prolongation |
| Severity: serious (n = 6); life-threatening (n = 1); QTc increase from 400 ms to 709 ms in an ICU patient) | ||
| Location: ICU (n = 5), non-ICU inpatient (n = 2) | ||
| Ondansetron–QT-prolonging agents | 2 | QTc prolongation |
| Severity: serious (n = 2) | ||
| Location: non-ICU inpatient (n = 2) | ||
| Sotalol–QT-prolonging agents | 2 | QTc prolongation |
| Severity: serious (n = 2) | ||
| Location: non-ICU inpatient (n = 2) | ||
| Warfarin–sulfonamides | 2 | Minor bleeding, therapeutic INR (n = 1) |
| Hemoptysis with elevated INR (5.9) (n = 1) | ||
| Severity: significant (n = 1), serious (n = 1) | ||
| Location: outpatient (n = 1), non-ICU inpatient (n = 1) | ||
| Escitalopram–QT-prolonging agents | 2 | QTc prolongation |
| Severity: serious (n = 2) | ||
| Location: ICU (n = 1); non-ICU inpatient (n = 1) | ||
| Lithium–thiazide diuretics | 2 | Elevated lithium level with symptoms (1 patient with level increase from 0.2 to 1.43 mEq/L and complained of nausea (normal range, 0.5-1.3 mEq/L); second patient with level increase from 0.78 to 1.36 mEq/L and symptoms of neurodecline (possibly due to lithium noted in chart) |
| Severity: serious (n = 2) | ||
| Location: outpatient (n = 2) | ||
| Methadone–QT-prolonging agents | 1 | QTc prolongation |
| Severity: serious (n = 1) | ||
| Location: non-ICU inpatient (n = 1) | ||
| Ciprofloxacin–QT-prolonging agents | 1 | QTc prolongation |
| Severity: serious (n = 1) | ||
| Location: non-ICU inpatient (n = 1) | ||
| Simvastatin (>20 mg)– amlodipine | 1 | Elevated CK (201 baseline to 535) |
| Severity: significant (n = 1) | ||
| Location: ICU (n = 1) | ||
ADE: adverse drug event; CK; creatine kinase; DDI: drug–drug interaction; ICU: intensive care unit; INR: international normalized ratio; QTc: corrected QT interval; TNF: tumor necrosis factor.