Delirium – QTc and antipsychotics

Strong caution against antipsychotics recommended with QTc > 500 ms or an absolute increase of 60 ms from baseline due to QTc prolonging effects and risk of Torsade de Pointes (TdP)

A QTc >500 ms carries a 2-to-3-fold higher risk of TdP. Each 10 ms prolongation adds 5-7% exponential increase of TdP.

Monitor with serial EKGs or telemetry especially if requiring multiple or high doses of antipsychotics

See Prevention of Torsade de Pointes in Hospital Settings (link to review article) for more information

Treat reversible causes of QTc prolongation

Ensure potassium >4.0, magnesium >2.0, calcium within normal limits (ionized, or corrected for albumin)

Stop QTc prolonging medications as able

See UpToDate for more recommendations

Frequently recheck EKGs and reevaluate need for antipsychotics

Continue to evaluate if an antipsychotic is still indicated. If so, you can recheck an EKG daily to see if the QTc improves as the clinical status changes or reversible causes of QTc prolongation are addressed.