with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.phenytoinsarilumab, phenytoin. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.primidonesarilumab, primidone. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.quinidinesarilumab, quinidine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.quininesarilumab, quinine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.rozanolixizumabrozanolixizumab will decrease the level or effect of sarilumab by receptor binding competition. Use Caution/Monitor. Coadministration of rozanolixizumab with medications that bind to the human neonatal Fc receptor may lower systemic exposures and effectiveness of such medications. Closely monitor for reduced effectiveness of medications that bind to the human neonatal Fc receptor. If long-term use of such medications is essential, consider discontinuing rozanolixizumab and using alternative therapies.sirolimussarilumab, sirolimus. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.tacrolimussarilumab, tacrolimus. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.theophyllinesarilumab, theophylline. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.trastuzumabtrastuzumab, sarilumab. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Neutropenia or febrile neutropenia incidence were increased when trastuzumab was coadministered with myelosuppressive chemotherapy.trastuzumab deruxtecantrastuzumab deruxtecan, sarilumab. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Neutropenia or febrile neutropenia incidence were increased when trastuzumab was coadministered with myelosuppressive chemotherapy.ublituximabublituximab and sarilumab both increase immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely. Owing to potential additive immunosuppressive effects, consider duration of effect and mechanism of action of these therapies if coadministeredvalproic acidsarilumab, valproic acid. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.zoster vaccine recombinantsarilumab decreases effects of zoster vaccine recombinant by pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressive therapies may reduce the effectiveness of zoster vaccine recombinant.Minor (0)adenovirus types 4 and 7 live, oralSerious - Use Alternative (1)sarilumab, adenovirus types 4 and 7 live, oral. immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug. Avoid concurrent use of live virus vaccines, owing to potentially increased risk of infections. The interval between live vaccinations and initiation of sarilumab therapy should be in accordance with current vaccination guidelines regarding immunosuppressive agents.anthrax vaccine adsorbedSerious - Use Alternative (1)sarilumab, anthrax vaccine adsorbed. immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug. Avoid concurrent use of live virus vaccines, owing to potentially increased risk of infections. The interval between live vaccinations and initiation of sarilumab therapy should be in accordance with current vaccination guidelines regarding immunosuppressive agents.axicabtagene ciloleucelSerious - Use Alternative (1)sarilumab, axicabtagene ciloleucel. Either increases effects of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.BCG vaccine liveSerious - Use Alternative (1)sarilumab, BCG vaccine live. immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug. Avoid concurrent use of live virus vaccines, owing to potentially increased risk of infections. The interval between live vaccinations and initiation of sarilumab therapy should be in accordance with current vaccination guidelines regarding immunosuppressive agents.brexucabtagene autoleucelSerious - Use Alternative (1)sarilumab, brexucabtagene autoleucel. Either increases effects of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.carbamazepineMonitor Closely (1)sarilumab, carbamazepine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.cholera vaccineSerious - Use Alternative (1)sarilumab, cholera vaccine. immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug. Avoid concurrent use of live virus vaccines, owing to potentially increased risk of infections. The interval between live vaccinations and initiation of sarilumab therapy should be in accordance with current vaccination guidelines regarding immunosuppressive agents.ciltacabtagene autoleucelSerious - Use Alternative (1)sarilumab, ciltacabtagene autoleucel. Either increases effects of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.clonidineMonitor Closely (1)sarilumab, clonidine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.cyclosporineMonitor Closely (1)sarilumab, cyclosporine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of certain cytokines during chronic inflammation; thus, sarilumab could normalize the formation of CYP450 enzymes thus decrease levels of CYP substrates. Upon initiation or discontinuation of sarilumab in patients who are receiving concomitant CYP450 substrates with a narrow therapeutic index, monitor therapeutic effect.dengue vaccineMonitor Closely (1)sarilumab decreases effects of dengue vaccine by immunosuppressive effects; risk of infection. Use Caution/Monitor. Immunosuppressive therapies (eg, irradiation, antimetabolites, alkylating agents, cytotoxic drugs, corticosteroids [greater than physiologic doses]) may reduce immune response to dengue vaccine.disopyramideMonitor Closely (1)sarilumab, disopyramide. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.efgartigimod alfaMonitor Closely (1)efgartigimod alfa will decrease the level or effect of sarilumab by receptor binding competition. Use Caution/Monitor. Coadministration of efgartigimod with medications that bind to the human neonatal Fc receptor may lower systemic exposures and effectiveness of such medications. Closely monitor for reduced effectiveness of medications that bind to the human neonatal Fc receptor. If long-term use of such medications is essential, consider discontinuing efgartigimod and using alternative therapies.efgartigimod/hyaluronidase SCMonitor Closely (1)efgartigimod/hyaluronidase SC will decrease the level or effect of sarilumab by receptor binding competition. Use Caution/Monitor. Coadministration of efgartigimod with medications that bind to the human neonatal Fc receptor may lower systemic exposures and effectiveness of such medications. Closely monitor for reduced effectiveness of medications that bind to the human neonatal Fc receptor. If long-term use of such medications is essential, consider discontinuing efgartigimod and using alternative therapies.fosphenytoinMonitor Closely (1)sarilumab, fosphenytoin. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of cytokines such as IL-6. Elevated IL-6 concentration may down-regulate CYP activity, such as in patients with RA, and, hence, increase drug levels compared with subjects without RA. Blockade of IL-6 signaling by IL-6 antagonists (eg, sarilumab) might reverse the inhibitory effect of IL-6 and restore CYP activity, leading to decreased drug concentrations. Caution when initiating or discontinuing sarilumab if coadministered with CYP450 substrates, especially those with a narrow therapeutic index.idecabtagene vicleucelSerious - Use Alternative (1)sarilumab, idecabtagene vicleucel. Either increases effects of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.isavuconazonium sulfateMonitor Closely (1)sarilumab and isavuconazonium sulfate both decrease immunosuppressive effects; risk of infection. Use Caution/Monitor.lisocabtagene maraleucelSerious - Use Alternative (1)sarilumab, lisocabtagene maraleucel. Either increases effects of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.lomustineMonitor Closely (1)lomustine and sarilumab both increase immunosuppressive effects; risk of infection. Use Caution/Monitor. Caution should be taken in patients on concomitant immunosuppressants or with impaired immune systems because of increased risk for serious infections.measles (rubeola) vaccineSerious - Use Alternative (1)sarilumab, measles (rubeola) vaccine. immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug. Avoid concurrent use of live virus vaccines, owing to potentially increased risk of infections. The interval between live vaccinations and initiation of sarilumab therapy should be in accordance with current vaccination guidelines regarding immunosuppressive agents.measles, mumps, rubella and varicella vaccine, liveSerious - Use Alternative (1)sarilumab, measles, mumps, rubella and varicella vaccine, live. immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug. Avoid concurrent use of live virus vaccines, owing to potentially increased risk of infections. The interval between live vaccinations and initiation of sarilumab therapy should be in accordance with current vaccination guidelines regarding immunosuppressive agents.mechlorethamineMonitor Closely (1)mechlorethamine, sarilumab. Either increases toxicity of the