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Liver function impairment - The pharmacokinetics are altered. No dosage adjustment is required in patients with hepatic function impairment, unless there is also concurrent severe renal function impairment. |
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Renal function impairment (severe) - The elimination of KLARIZON is reduced in patients with renal function impairment, especially those with a creatinine clearance of < 30 ml/min. The dose of KLARIZON should be halved or the dosing interval doubled in patients with a creatinine clearance of < 30 ml/min. |
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Rhabdomyolysis has been reported with concomitant use of KLARIZON and the HMGCoA reductase inhibitors e.g. simvastatin (SEE INTERACTIONS). |
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Rifabutin and rifampicin - May decrease serum concentration of KLARIZON by >50%. Co-administration has been reported to cause a higher incidence of uveitis compared to rifabutin alone (SEE INTERACTIONS). |
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Theophylline - The area under the plasma concentration-time curve is increased. Monitoring of theophylline serum concentrations is recommended (SEE INTERACTIONS). |
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Cross-resistance between KLARIZON and other macrolides, lincomycin and clindamycin have been reported. |
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Astemizole, cisapride, pimozide and terfenadine - Has resulted in cardiac arrhythmias, including QTc-interval prolongation, ventricular arrhythmia, ventricular tachycardia, ventricular fibrillation and torsade de pointes. Fatalities have occurred. The most likely cause is the inhibition of metabolism of these medicines by KLARIZON. Concurrent use is contra-indicated. See CONTRA-INDICATIONS. |
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Anticoagulants such as warfarin - KLARIZON may result in the potentiation of the effects of warfarin. Prothrombin time should be monitored closely. |
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Digoxin - KLARIZON has been shown to increase serum digoxin concentrations. Monitoring of digoxin serum concentrations is recommended. |
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Carbamazepine or other medicines metabolised by the cytochrome P450 enzyme system for example (alprazolam, cyclosporine, disopyramide, ergot alkaloids, methylprednisolone, midazolam, omeprazole, quinidine, sildenafil, simvastatin, tacrolimus, triazolam, vinblastine, phenytoin and valproate) - KLARIZON may be associated with increased levels of these medicines. Serum concentrations of these medicines may require monitoring. Rhabdomyolysis has been reported with concomitant use of KLARIZON and the HMGCoA reductase inhibitors e.g. simvastatin (SEE WARNINGS). |
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Rifabutin and rifampicin - May decrease serum concentration of KLARIZON by >50%. Co-administration has been reported to cause a higher incidence of uveitis compared to rifabutin alone (SEE WARNINGS). |
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Theophylline - The area under the plasma concentration-time curve is increased. Monitoring of theophylline serum concentrations is recommended (SEE WARNINGS). |
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Zidovudine - A decrease in the steady-state concentration of zidovudine may occur. Doses of zidovudine and KLARIZON should be taken at least 4 hours apart. |
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Ritonavir - The metabolism of KLARIZON is inhibited. No dosage reduction of KLARIZON is needed in patients with normal renal function. Patients with renal function impairment require a reduction in the dose of KLARIZON as follows: |
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Creatinine clearance 30 to 60 ml/min - Reduce dose by 50% |
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Creatinine clearance of < 30 ml/min - Reduce dose by 75% |