Drug Interactions between cinacalcet and etelcalcetide

GENERALLY AVOID: Concomitant use of the calcimimetics etelcalcetide and cinacalcet may lead to severe, life-threatening, hypocalcemia. The proposed mechanism is additive reduction in serum calcium levels through binding and activation of the calcium-sensing receptor on the parathyroid gland. Significant decreases in serum calcium may cause paraesthesias, myalgias, muscle spasms, seizures, QT interval prolongation, and ventricular arrhythmia. Both medications given alone may lead to severe hypocalcemia requiring treatment with therapies to increase serum calcium levels.

MANAGEMENT: Concomitant use of etelcalcetide and cinacalcet is not recommended. At least 7 days should elapse when switching from cinacalcet to etelcalcetide, and the corrected serum calcium level should be at or above the lower limit of the normal range. In addition, the corrected serum calcium level should be measured within one week of initiation or dose adjustment of either etelcalcetide or cinacalcet and monitored approximately every 4 weeks. The manufacturer product labeling should be consulted for management guidelines in the event of a reduction in corrected serum calcium levels below the lower limit of the normal range and/or symptoms hypocalcemia. Patients should also be advised to contact their health care professional if they experience symptoms of hypocalcemia, such as numbness or tingling in the fingers, toes, or around the mouth, muscle spasms, twitches or cramps, seizures, confusion, and irregular heartbeats.