Paxus PM Drug Interactions

In a Phase I trial of PAXUS PM (110-220 mg/m²) and cisplatin (50 or 75 mg/m²) given as sequential infusions, myelosuppression was more profound when cisplatin was administered before PAXUS PM than the alternate sequence (i.e., PAXUS PM administration before cisplatin). Pharmacokinetics data from these patients demonstrated a decrease in paclitaxel clearance when cisplatin was administered before PAXUS PM. Peripheral neuropathy may increase by the concurrent therapy. When the concurrent therapy is given, dose adjustment or prolonged dose interval should be considered with the observation of patients.
The metabolism of drug is catalyzed by cytochrome P450 isoenzymes CYP2C8 and CYP3A4. As there are no adequate clinical studies for drug interactions, caution should be taken when PAXUS PM is administered with known substrates or inhibitors (such as ritovanir, saquinavir, indinavir, and nelfinavir) of cytochrome P450 isoenzymes CYP2C8 and CYP3A4.
The metabolism of paclitaxel may be suppressed by Vitamin A, azole antifungal agents (e.g. ketoconazole, miconazole), macrolide hormones (e.g. ethinyl estradiol), dihydropyridine calcium channel inhibitor (e.g. nifedipine), terfenadine, cyclosporine, verapamil, quinidine, midazolam, phenacetin, ritonavir, saquinavir, indinavir and nelfinavir. At concurrent administration, dose adjustment or prolonged dosing interval should be considered with the observation of patients.
At the concurrent radiotherapy to the chest, severe esophagitis or lung enteritis was reported and myelosuppression may be increased.
The concurrent therapy with other antitumor drugs may increase the risk of myelosuppression.