Butyrophenones

BUTYROPHENONES

Droperidol (0.625–1.25 mg) was previously used routinely for PONV prophylaxis. Given at the end of the procedure it blocks dopamine receptors that contribute to the development of PONV. Despite its effectiveness, many practitioners no longer rou-tinely administer this medication because of a U.S. Food and Drug Administration (FDA) black box warning related to concerns that doses described in the product labeling (“package insert”) may lead to QT prolongation and development of torsades des pointes dysrhythmia. However, the doses rel-evant to the FDA warning, as acknowledged by the FDA, were those used for neurolept anesthesia (5–15 mg), not the much smaller doses employed for PONV. Cardiac monitoring is warranted when large doses of the drug are used. There is no evi-dence that use of droperidol at the doses routinely employed for PONV management increases the risk of sudden cardiac death in the perioperative population.

As with other drugs that antagonize dopamine, droperidol use in patients with Parkinson’s disease and in patients manifesting extrapyramidal signs should be carefully considered.

The phenothiazine, prochlorperazine (Com-pazine), which affects multiple receptors (hista-minergic, dopaminergic, muscarinic), may be used for PONV management. It may cause extrapyrami-dal and anticholinergic side effects. Promethazine (Phenergan) works primarily as an anticholinergic agent and antihistamine and likewise can be used to treat PONV. As with other agents of this class, anticholinergic effects (sedation, delirium, confu-sion, vision changes) can complicate the postop-erative period.