DRUG INTERACTIONS Drug Interactions
No formal drug interaction studies have been conducted with VELCADE.
In vitro studies with human liver microsomes indicate that bortezomib is primarily a substrate for cytochrome P450 3A4, 2C19, and 1A2. Patients who are concomitantly receiving VELCADE and drugs that are inhibitors or inducers of cytochrome P450 3A4 should be closely monitored for either toxicities or reduced efficacy (see CLINICAL PHARMACOLOGY/ Pharmacokinetics-Drug Interactions).
During clinical trials, hypoglycemia and hyperglycemia were reported in diabetic patients receiving oral hypoglycemics. Patients on oral antidiabetic agents receiving VELCADE treatment may require close monitoring of their blood glucose levels and adjustment of the dose of their antidiabetic medication.
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OVERDOSAGE
There is no known specific antidote for VELCADE overdosage (see PRECAUTIONS and DOSAGE AND ADMINISTRATION). In humans, fatal outcomes following the administration of more than twice the recommended therapeutic dose have been reported, which were associated with the acute onset of symptomatic hypotension and thrombocytopenia. In the event of an overdosage, the patient’s vital signs should be monitored and appropriate supportive care given.
Studies in monkeys and dogs showed that IV bortezomib doses as low as 2 times the recommended clinical dose on a mg/m2 basis were associated with increases in heart rate, decreases in contractility, hypotension, and death. In dog studies, a slight increase in the corrected QT interval was observed at doses resulting in death. In monkeys, doses of 3.0 mg/m2 and greater (approximately twice the recommended clinical dose) resulted in hypotension starting at 1 hour post-administration, with progression to death in 12 to 14 hours following drug administration.
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