Drug Interaction Report

GENERALLY AVOID: The concomitant use of roflumilast with immunosuppressive agents has not been adequately studied. Roflumilast is a selective phosphodiesterase 4 (PDE4) inhibitor and a nonsteroidal anti-inflammatory agent. In experimental models and in vitro studies, roflumilast has exhibited immunomodulatory effects. Specifically, roflumilast and its active metabolite, roflumilast N-oxide, suppress the release of inflammatory mediators including leukotriene B4, reactive oxygen species, tumor necrosis factor alpha, interferon gamma, and granzyme B. Roflumilast also reduces sputum neutrophils and attenuates influx of neutrophils and eosinophils into the airways.

MANAGEMENT: According to the product labeling for roflumilast in some countries such as Canada and the U.K., concomitant use with immunosuppressive agents such as methotrexate, azathioprine, infliximab, etanercept, and systemic corticosteroids (except when used short-term, e.g., in the treatment of COPD exacerbations) should be avoided if possible. Due to a lack of clinical experience, treatment with roflumilast should not be initiated, or existing treatment should be stopped, in patients receiving immunosuppressive agents and in patients with severe acute infectious diseases, cancers (except basal cell carcinoma), or severe immunological diseases (e.g., HIV infection, multiple sclerosis, lupus erythematosus, progressive multifocal leukoencephalopathy).

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of 21-desdeflazacort, the active metabolite of deflazacort that is formed by esterases after oral administration and further metabolized by CYP450 3A4 to several inactive metabolites. The proposed mechanism is inhibition of CYP450 3A4-mediated metabolism in the gut wall by certain compounds present in grapefruit. In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Increased systemic exposure to 21-desdeflazacort may increase the risk of corticosteroid adverse effects such as hypercorticism, hyperglycemia, adrenal suppression, immunosuppression, hypertension, salt and water retention, electrolyte abnormalities, behavioral and mood disturbances, posterior subcapsular cataracts, glaucoma, bone loss, and growth retardation in children and adolescents.

MANAGEMENT: Deflazacort should not be administered with grapefruit juice.

Food intake does not affect the total exposure to roflumilast and its pharmacologically active N-oxide metabolite, but delays the time to maximum concentration (Tmax) of roflumilast by one hour and reduces its peak plasma concentration (Cmax) by approximately 40%. The Tmax and Cmax of
roflumilast N-oxide are unaffected. Roflumilast may be taken with or without food.