Interactions between sensipar(cinacalcet) and Antinaus 50 (promethazine)
promethazine and cinacalcet (Moderate Drug-Drug)
MONITOR: Coadministration with cinacalcet may increase the plasma concentrations of drugs that are substrates of the CYP450 2D6 isoenzyme. The mechanism is decreased clearance due to inhibition of CYP450 2D6 activity by cinacalcet, which is expected to occur in patients who are CYP450 2D6 extensive metabolizers (approximately 93% of Caucasians and more than 98% of Asians and individuals of African descent). Concurrent administration of cinacalcet (25 or 100 mg) increased the systemic exposure of amitriptyline (50 mg) and its active metabolite, nortriptyline, by approximately 20% in CYP450 2D6 extensive metabolizers. However, because amitriptyline is metabolized by multiple CYP450 isoenzymes in addition to 2D6, the degree of interaction with cinacalcet may be less than that expected for other drugs that are primarily metabolized by 2D6.
MANAGEMENT: Caution is advised if cinacalcet must be used concurrently with medications that undergo metabolism by CYP450 2D6, particularly those with a narrow therapeutic range (e.g., class IC antiarrhythmic agents, phenothiazines, certain beta blockers, and most tricyclic antidepressants). Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever cinacalcet is added to or withdrawn from therapy.
