Can chlordiazepoxide (Librium) induce ventricular tachycardia (VT)?

Chlordiazepoxide and Ventricular Tachycardia Risk

Chlordiazepoxide does not induce ventricular tachycardia (VT) based on available evidence. The drug is not listed among medications known to cause ventricular arrhythmias in major cardiology guidelines, and its documented cardiac effects are limited to withdrawal symptoms in neonates.

Evidence from Guidelines and Literature

Absence from Pro-Arrhythmic Drug Lists

The 2015 ESC Guidelines for Management of Ventricular Arrhythmias comprehensively discuss drug-induced pro-arrhythmia and specifically identify medications that cause VT, including:

• QT-prolonging agents (antibiotics like quinolones, azithromycin, erythromycin, clarithromycin) 1
• Sodium channel blockers (tricyclic antidepressants, Class IC antiarrhythmics) 1
• Antipsychotics (thioridazine, haloperidol) 1
• Other cardiac medications (sotalol, digitalis, sympathomimetics) 1, 2

Chlordiazepoxide is notably absent from these comprehensive lists of pro-arrhythmic medications 1.

Documented Effects of Chlordiazepoxide

The only cardiac-related documentation for chlordiazepoxide appears in neonatal withdrawal literature, where it causes:

• Irritability and tremors in neonates exposed in utero 1
• Withdrawal signs that may start as late as 21 days after birth 1
• No mention of ventricular arrhythmias or tachycardia 1

Benzodiazepine Class Effects

Research on benzodiazepines and cardiac rhythm shows:

• Benzodiazepines like midazolam, alprazolam, and chlordiazepoxide cause tachycardia through vagolytic effects (suppression of vagal tone), not through direct pro-arrhythmic mechanisms 3
• This tachycardia is sinus tachycardia, not ventricular tachycardia 3
• The effect is mediated through GABA receptors and can be blocked by atropine or benzodiazepine antagonists 3
• Benzodiazepines are actually recommended for sedation in patients with severe cardiac dysfunction due to their favorable cardiovascular stability profile compared to other sedatives 4

Clinical Context

When VT Does Occur with Psychotropic Drugs

The literature documents VT with specific psychotropic agents, but not benzodiazepines:

• Phenothiazines (particularly thioridazine) caused ventricular tachycardia in 5 of 8 reported cases, including one fatality 5
• Tricyclic antidepressants produce QRS prolongation and can induce VT 1, 5
• These agents have fundamentally different mechanisms (sodium channel blockade, QT prolongation) than benzodiazepines 1, 2

Practical Implications

If a patient on chlordiazepoxide develops VT, look for alternative causes:

• Underlying structural heart disease 1
• Concomitant QT-prolonging medications 1
• Electrolyte abnormalities (hypokalemia, hypomagnesemia) 1
• Other pro-arrhythmic drugs the patient may be taking 1

The absence of chlordiazepoxide from multiple comprehensive cardiology guidelines addressing drug-induced arrhythmias, combined with its distinct pharmacologic profile as a benzodiazepine, strongly indicates it does not induce VT 1.