Table 5.
Chloroquine and hydroxychloroquine drug interactions.
| Drugs that cause QT interval prolongation | ||
| Macrolides (erythromycin, clarithromycin and azithromycin) | Have additive/synergistic effects on QT interval prolongation, increase chances of toxic arrhythmias, polymorphic ventricular fibrillation and death | |
| Quinolones (ciprofloxacin and levofloxacin) | ||
| Anti-arrhythmic (amiodarone and sotalol) | ||
| Antifungal (ketoconazole and fluconazole) | ||
| Antidepressants (amitriptyline and dothiepin) | ||
| Anti-emetics (ondansetron, granisetron and dolasetron) | ||
| Drugs that inhibit cytochrome 450 enzyme | ||
| Cimetidine | Increases CQ and HCQ levels and possible toxicity | |
| Diltiazem and verapamil | ||
| Fluoxetine (Prozac), paroxetine (Paxil) | ||
| Metronidazole (Flagyl) | ||
| Drugs that are eliminated through the P-glycoprotein (P-gp) eliminator pathway (CQ and HCQ Inhibit of P-gp) | ||
| Digoxin | Increases serum levels of digoxin and ciclosporin and needs close monitoring | |
| Ciclosporin | ||
| Drugs that compete with the metabolism of CQ and HCQ | ||
| Metoprolol | Increases bioavailability of metoprolol | |
| Tamoxifen | Increases chances of retinopathy | |
| Methotrexate | Reduces absorption of methotrexate and reduces methotrexate hepatotoxicity | |
| Drugs which reduce the absorption of CQ and HCQ either by binding or altering gastric pH | ||
| Antacids, kaolin and proton pump inhibitors | Reduce absorption of CQ and HCQ; maintain a 4-hour period between intake of two classes of drugs | |