The intravenous route is not FDA approved and is generally not recommended except when no other alternatives are available. Intravenous administration appears to be associated with a higher risk of QT prolongation and torsade de pointes (TdP) than other forms of administration. The manufacturer recommends ECG monitoring for QT prolongation and arrhythmias if IV administration is required. A dose in the range of 1 to 5 mg IV has been suggested, with the dose being repeated at 30 to 60 minute intervals, if needed. A maximum IV dose has not been established. The lowest effective dose should be used in conjunction with conversion to oral therapy as soon as possible.
There is growing evidence that chronic hyperprolactinemia from antipsychotics can cause osteoporosis and an increased risk of hip fracture. A recent case-control analysis of a large general practice database in the United Kingdom showed that the risk of hip fracture was times higher in patients taking prolactin-raising antipsychotics compared with the general population. 20 Physicians should routinely inquire about symptoms that might reflect hyperprolactinemia in patients taking prolactin-raising antipsychotics and, if present, measure the serum prolactin level. Presence of osteoporosis, sexual side effects, or prolactin-dependent breast cancer may necessitate switching to an antipsychotic that does not raise prolactin levels, such as aripiprazole (Abilify) or quetiapine. 21