Drug Interaction Report

MONITOR CLOSELY: The use of the CD20-directed cytolytic antibody ublituximab with other immune-modulating or immunosuppressive therapy, including immunosuppressant doses of corticosteroids may increase the risk of infections. Adverse events most commonly reported with ublituximab alone included upper respiratory tract infections and urinary tract infections. However, serious and life-threatening infections, such as hepatitis B virus (HBV) reactivation have been reported in relapsing multiple sclerosis (RMS) controlled clinical trials with ublituximab, as well as fatal infections. In addition, Progressive Multifocal Leukoencephalopathy (PML) due to JC virus infection, fulminant hepatitis, hepatic failure, and death caused by HBV reactivation have been reported in patients treated with other anti-CD20 antibodies; however, these adverse events were not reported in RMS controlled clinical trials with ublituximab.

MANAGEMENT: The increased risk of additive immunosuppression should be considered if coadministering ublituximab with other immunosuppressive therapy. In addition, the prolonged immunosuppressant effects and mode of action of other immunosuppressant drugs such as daclizumab, fingolimod, natalizumab, teriflunomide, or mitoxantrone should be considered prior to starting ublituximab therapy. Patients should be advised to immediately notify their doctor if they develop signs or symptoms of infection, including HBV reactivation, upper or lower respiratory tract infection, urinary tract infections, herpes-related infection, or PML.

GENERALLY AVOID: Concurrent use of ethanol and phenothiazines may result in additive CNS depression and psychomotor impairment. Also, ethanol may precipitate dystonic reactions in patients who are taking phenothiazines. The two drugs probably act on different sites in the brain, although the exact mechanism of the interaction is not known.

MANAGEMENT: Patients should be advised to avoid alcohol during phenothiazine therapy.