Risk of hypocalcaemia. Measure serum Ca prior to treatment initiation, 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. Risk of adynamic bone in patients w/ PTH <100 pg/mL. +ve for binding Abs in patients w/ SHPT. Co-administration w/ other medicinal products known to lower serum Ca. Hepatic impairment. Pregnancy & lactation. Childn <18 yr.