For patients with cardiac disease or some of the risk factors for prolonged QTc, Dr. Ernst recommends that psychiatrists order a baseline and steady state EKG, with intermittent QTc monitoring if warranted. “Closely weigh the risks and benefits and consider avoiding the antipsychotic if the baseline QTc is over 500 milliseconds,” she said. “Avoid low-potency typicals, IV haloperidol, and ziprasidone.”
For patients on IV haloperidol, she recommends obtaining a baseline and at least daily QTc, as well as electrolyte monitoring. Some guidelines suggest continuous EKG monitoring for those with baseline QTc of more than 500 milliseconds, risk factors, and/or high dose requirements. “If the QTc increases beyond 500 milliseconds, check and replete electrolytes, review the medication regimen for other agents that prolong the QTc, consider holding until the QTc is less than 500 milliseconds, consider alternative agents, and perform frequent EKG monitoring and a cardiology consult if you decide to continue,” she said.
In patients without any risk factors for prolonged QTc, there is no consensus on obtaining a baseline QTc or doing serial QTc monitoring. “Do a careful risk assessment, and if the QTc increases beyond 500 milliseconds or greater than 60 milliseconds from baseline during treatment, use the same approach as in high-risk patients,” Dr. Ernst said. “Maintain an updated medication list, and if QT prolonging medications are added or new pharmacokinetic interactions occur, approach them the same as you would a high-risk patient.”
She reported having no financial disclosures.