What can be given to a patient with a prolonged QTc (corrected QT interval) interval for anxiety?

Management of Anxiety in a Patient with QTc 594 ms

Benzodiazepines are the safest anxiolytic option for this patient, as they do not prolong the QT interval and have no reported changes in QT duration in clinical use. 1

Immediate Priorities

With a QTc of 594 ms, this patient is at critical risk for torsades de pointes and sudden cardiac death. 2 Before treating anxiety, you must:

• Discontinue all QT-prolonging medications immediately 1
• Correct electrolyte abnormalities, particularly hypokalemia and hypomagnesemia 2, 3
• Initiate continuous cardiac telemetry monitoring until QTc normalizes to <500 ms 2
• Repeat 12-lead ECG every 2-4 hours to track QTc changes 2

Safe Anxiolytic Options

First-Line: Benzodiazepines

Benzodiazepines are the only anxiolytic class with no QT-prolonging effects. 1 In vitro studies show both inhibition and activation of potassium currents, but no changes in QT duration have been reported in clinical use. 1

Lorazepam is preferred given its predictable pharmacokinetics:

• Initial dosing: 1-2 mg/day in divided doses for elderly or at-risk patients 4
• Standard dosing: 2-3 mg/day in 2-3 divided doses for most patients 4
• Maximum: up to 10 mg/day if needed, with largest dose at bedtime 4
• No cardiac monitoring required beyond baseline assessment 1

Alternative: Pregabalin

Pregabalin is another safe option as it binds selectively to GABA receptors and has not been associated with QT prolongation. 1

Medications to ABSOLUTELY AVOID

Antidepressants - High Risk

All SSRIs and SNRIs must be avoided in this patient:

• Citalopram and escitalopram have FDA/EMA dose restrictions specifically due to QT prolongation 1
• SSRIs increase cardiac arrest risk (OR 1.21) and are associated with QTc prolongation 1
• Tricyclic antidepressants carry even higher risk (OR 1.69 for cardiac arrest) 1

Antipsychotics - Extremely High Risk

Never use antipsychotics for anxiety in this patient:

• Thioridazine prolongs QTc by 35 ms 5
• Haloperidol and olanzapine prolong QTc by 4-6 ms 5
• All antipsychotics block IKr potassium current, the primary mechanism for drug-induced torsades de pointes 5

Antiemetics - Contraindicated

Metoclopramide is specifically contraindicated with baseline QTc >500 ms:

• Listed as high-risk QT-prolonging antiemetic 6
• Should be discontinued if QTc >500 ms or increases >60 ms from baseline 6

Critical Risk Factors Present

This patient has multiple compounding risk factors that increase torsades de pointes risk:

• QTc >500 ms - the threshold where ACC/AHA/HRS guidelines mandate drug discontinuation 1
• Anxiety itself is an independent risk factor for QTc prolongation (OR 1.80 for severe anxiety in men) 7
• Female sex increases risk if patient is female 2, 7
• Any concurrent medications must be reviewed for QT effects 6, 3

Monitoring Protocol

Even with benzodiazepines (which are safe), maintain cardiac vigilance:

• Continuous telemetry until QTc <500 ms 2
• Serial ECGs every 2-4 hours initially 2
• Daily electrolytes (potassium, magnesium, calcium) 2, 3
• Review all medications using resources like www.crediblemeds.org 1

Common Pitfalls to Avoid

Do not use beta-blockers for anxiety in this patient - while sometimes used for anxiety, they should be used cautiously when QTc >500 ms due to risk of pause-dependent torsades de pointes, especially with bradycardia. 1

Do not assume mood stabilizers are safe - while carbamazepine, lamotrigine, and valproate are generally not associated with severe arrhythmia, lithium can cause bradycardia, T-wave changes, and AV block. 1

Polypharmacy is the primary driver of drug-induced QTc prolongation and complications - even one additional QT-prolonging drug creates dangerous synergy. 8, 3