Table 1

Distribution and types of the 107 hazardous or contraindicated drug combinations recorded in the elderly and non-elderly patients

Type of HCDC
Polypharmacy with QTAP653
QTAP plus bradycardia inducing drugs23
ACE inhibitors plus potassium sparing diuretics or potassium supplement92
AP plus levodopa60
Haloperidol plus lithium31
Lamotrigine plus valproic acid07
AED plus oral contraceptives07
Clozapine plus carbamazepine03
Carbamazepine plus dextropropoxyphen03
Naltrexone plus codeine01
LMW heparin plus NSAID01
Types of iatrogenic risk carried by the HCDC recorded
Cardiotoxicity (torsade de pointe)856
Therapeutic inefficacy68
 Antagonistic interaction at the receptor level61
 Antagonistic interaction through increased clearance mechanisms07
Dermatologic toxicity (epidermal neurolysis)07
Neurotoxicity (delirium)34
Haematopoietic toxicity (agranulocytosis)03
  • ACE inhibitors, angiotensin converting enzyme inhibitors; AED, antiepileptic drugs; AP, antipsychotics; EP, elderly patients; HCDC, hazardous or contraindicated drug combination; LMW heparin, low molecular weight heparin; NEP, non-elderly patients; NSAID, non-steroidal anti-inflammatory drug; QTAP, QT prolonging antipsychotics.