Table 3. Non-psychotropics Associated with QT Prolongation.
| Antibiotics |
| Erythromycin |
| Clarithromycin |
| Ampicillin |
| Co-trimoxazole |
| Pentamidine |
| Some 4-quinolones affect QTc – see manufacturers’ literature |
| Antimalarials |
| Chloroquine |
| Mefloquine |
| Quinine |
| Antiarrhythmics |
| Quinidine |
| Disopyramide |
| Procainamide |
| Sotalol |
| Amiodarone |
| Bretylium |
| Other Medication |
| Amantadine |
| Cyclosporin |
| Diphenhydramine |
| Hydroxyzine |
| Nicardipine |
| Tamoxifen |
| Note: Beta 2 agonists and sympathomimetics may provoke torsades de pointes in patients with prolonged QTc. |
| ECG Monitoring |
Measure QTc in all patients prescribed antipsychotics:
|
| Metabolic Inhibition |
| The effect of drugs on the QTc interval is usually plasma level-dependent. Drug interactions are therefore important, especially when metabolic inhibition results in increased plasma levels of the drug affecting QTc. Commonly used metabolic inhibitors include fluvoxamine, fluoxetine, paroxetine and valproate. |
Source: Adapted from the Maudsley Prescribing Guidelines in Psychiatry.1Used with permission from Wiley Blackwell.