Risk of hypocalcaemia; adynamic bone in patients w/ PTH levels <100 pg/mL. Measure serum Ca levels prior to treatment, w/in 1 wk of initiation or dose adjustment & every 4 wk during treatment. Ventricular arrhythmia & QT prolongation secondary to hypocalcaemia. Patients w/ history of convulsion disorder or CHF. Monitor for positive binding Abs in SHPT patients treated w/ Parsabiv for up to 6 mth. Co-administration w/ drugs lowering serum Ca. Certain potential manifestations of hypocalcaemia may affect ability to drive or operate machinery. Pregnancy & lactation. Childn & adolescents <18 yr.