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Hi, I'm Mike Gibson, a professor of medicine from Harvard Medical School. Today, we're talking about the optimal dose of a new drug, betrixaban in thromboprophylaxis in the acutely ill medical patient. Well, the key to drug development is finding the right dose. If you under dose an anticoagulant, you'll have thrombotic events. If you overdose in anticoagulant, you'll obviously have bleeding events. The optimal dose is a dose that maximizes effectiveness while simultaneously minimizing bleeding.
Looking across all different fields and all different types of agents, you see this U-shape relationship between the dose of an anticoagulant and antiplatelet and effectiveness. With Heparin, we learned that the optimal PTT is 50 to 70 after a lytic agent. With Warfarin, we've learned that the optimal INR is two to three, and we've learned with aspirin that higher doses are not always better, that the optimal dose appears to be a fairly low dose of 75 to 150 milligrams a day.
Well, betrixaban had been studied in about 1,200 patients prior to the large trial we undertook in VTE Prophylaxis and the optimal dose had previously been found to be about 80 milligrams. That is the dose that we studied in the APEX trial, comparing betrixaban to enoxaparin. Now, the FDA label recommendations are shown here. The recommended dose of betrixaban is a loading dose of 160 milligrams, followed by 80 milligrams once daily. This should be given for 35 to 42 days. However, in patients with severe renal impairment, that is patients with a clearance of 15 to 30, using the Cockcroft-Gault equation, the recommended dose of betrixaban, is a load of 80, followed by a half dose of 40 milligram once a day. Again, the duration of treatment should be 35 to 42 days.
If a patient's on a PGP inhibitor, again, the loading dose should again be halved to 80 milligrams. Again, the maintenance dose should be halved to 40 milligrams daily. Again, complete the course of 35 to 42 days. If a patient misses a dose, and they don't take the drug on time, the dose should be taken as soon as possible in the same day. Please don't double the dose to make up for a missed dose. To wrap up, in general, for most patients, the loading dose of Betrixaban is 160 milligrams followed by a maintenance dose of 80 milligrams. For patients with moderate severe renal impairment, or strong PGP inhibitors, please reduce that dose to half. A loading dose of 80 milligrams followed by a maintenance dose of 40 milligrams.
Thank you and I hope you've enjoyed this segment.