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Table 4 Prevalence of the QT-DDIs, TdP risk, therapeutic classes, severity and documentation of drugs involved in QT DDIs

From: Frequency, characteristics and risk factors of QT interval prolonging drugs and drug-drug interactions in cancer patients: a multicenter study

Classification scheme Interacting drugs: n (%)a
TdP riskb
 Known risk of TdP (List 1) 345 (59.9)
 Possible risk of TdP (List 2) 27 (4.7)
 Conditional risk of TdP (List 3) 39 (6.8)
 Not included in AZCERT QT drug list (List 4) 165 (28.6)
Therapeutic classes (ATC code)
 Antimicrobial (J) 209 (36.3)
 Antiemetic (A04) 200 (34.7)
 Antipsychotic (N05A) 157 (27.3)
 Muscle relaxant (M03) 3 (0.5)
 Kinase inhibitor (L01XE) 3 (0.5)
 Antidiarrheal (A) 2 (0.4)
 Anticancer (L01) 2 (0.4)
 Antidepressant (N06A) 2 (0.4)
Classification on the basis of severityc QT-DDIs: n (%)d
Major 288 (100)
Classification on the basis of documentationc QT-DDIs: n (%)d
Fair 288 (100)
  1. AZCERT Arizona Center for Education and Research on Therapeutics, TdP torsades de pointes, QT DDIs QT prolonging drug-drug interactions, ATC Anatomical Therapeutic Chemical
  2. aPercentage calculated in number of all interacting drugs i.e., 576
  3. bTdP risk was based on the AZCERT QT drugs lists
  4. cSeverity and documentation were based on Micromedex DrugReax classification
  5. dPercentage calculated in total number of QT-DDIs i.e., 288