Drug Interaction Report

MONITOR: Concomitant use of immunosuppressive or myelosuppressive agents with denosumab may increase the risk of serious infections. Denosumab binds to and inhibits the receptor activator of nuclear factor kappa-B ligand (RANKL), which is expressed on activated T and B lymphocytes and in lymph nodes. Thus, denosumab alone may increase the risk of infections. In a clinical trial of over 7800 women with postmenopausal osteoporosis, the incidence of nonfatal serious infections was 3.3% in the placebo group and 4.0% in the denosumab group. Specifically, hospitalizations due to skin infections including erysipelas and cellulitis (<0.1% placebo vs. 0.4% denosumab) and serious infections in the abdomen (0.7% placebo vs. 0.9% denosumab), urinary tract (0.5% placebo vs. 0.7% denosumab), and ear (0.0% placebo vs. 0.1% denosumab) were reported. Endocarditis was reported in no placebo patients and 3 denosumab-treated patients. There was no difference in the incidence of opportunistic infections or infections resulting in death between the placebo and denosumab groups. The overall incidence of infections was also similar between the two groups.

MANAGEMENT: Caution is advised if denosumab must be used in combination with immuno- or myelosuppressive agents. Patients should be advised to contact their physician if they develop signs and symptoms of infection such as fever, chills, diarrhea, sore throat, muscle aches, shortness of breath, blood in phlegm, weight loss, red or inflamed skin, body sores, and pain or burning during urination. The need for continued denosumab therapy should be assessed when serious infections occur during treatment.

GENERALLY AVOID: The consumption of alcohol during therapy with leflunomide may potentiate the risk of liver injury. Leflunomide has been associated with hepatotoxicity, including elevated liver transaminases, hepatitis, jaundice/cholestasis, hepatic failure, and acute hepatic necrosis,

MANAGEMENT: Patients should be advised to avoid excessive alcohol use during leflunomide treatment.