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