Distribution and types of the 107 hazardous or contraindicated drug combinations recorded in the elderly and non-elderly patients
| EP | NEP | |
|---|---|---|
| Type of HCDC | ||
| Polypharmacy with QTAP | 6 | 53 |
| Haloperidol–phenothiazines | 4 | 40 |
| Haloperidol–benzamides | 0 | 4 |
| Benzamides–phenothiazines | 2 | 6 |
| Phenothiazines–phenothiazines | 0 | 2 |
| Benzamides–benzamides | 0 | 1 |
| QTAP plus bradycardia inducing drugs | 2 | 3 |
| QTAP–pyridostigmine | 0 | 3 |
| QTAP–amiodarone | 2 | 0 |
| ACE inhibitors plus potassium sparing diuretics or potassium supplement | 9 | 2 |
| AP plus levodopa | 6 | 0 |
| Haloperidol plus lithium | 3 | 1 |
| Lamotrigine plus valproic acid | 0 | 7 |
| AED plus oral contraceptives | 0 | 7 |
| Clozapine plus carbamazepine | 0 | 3 |
| Carbamazepine plus dextropropoxyphen | 0 | 3 |
| Naltrexone plus codeine | 0 | 1 |
| LMW heparin plus NSAID | 0 | 1 |
| Total | 26 | 81 |
| Types of iatrogenic risk carried by the HCDC recorded | ||
| Cardiotoxicity (torsade de pointe) | 8 | 56 |
| Additive | 6 | 53 |
| Potentiated | 2 | 3 |
| Therapeutic inefficacy | 6 | 8 |
| Antagonistic interaction at the receptor level | 6 | 1 |
| Antagonistic interaction through increased clearance mechanisms | 0 | 7 |
| Hyperkalaemia | 9 | 2 |
| Dermatologic toxicity (epidermal neurolysis) | 0 | 7 |
| Neurotoxicity (delirium) | 3 | 4 |
| Haematopoietic toxicity (agranulocytosis) | 0 | 3 |
| Bleeding | 0 | 1 |
| Total | 26 | 81 |
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.