Can Zyprexa (olanzapine) be given to a patient with bradycardia?

Can Zyprexa Be Given With a Pulse of 49?

Zyprexa (olanzapine) should be used with extreme caution in a patient with a heart rate of 49 bpm, as it can cause bradycardia and hypotension, potentially worsening the existing bradycardia and leading to hemodynamic instability.

Primary Cardiovascular Risks of Olanzapine

Olanzapine carries significant risk of bradycardia and hypotension, particularly during initial dosing. The FDA label explicitly warns that olanzapine may induce orthostatic hypotension associated with dizziness, tachycardia, bradycardia, and syncope, especially during initial dose-titration, reflecting its α1-adrenergic antagonistic properties 1. Three healthy volunteers in Phase 1 studies experienced hypotension, bradycardia, and sinus pauses of up to 6 seconds that spontaneously resolved 1.

Evidence from Overdose and Clinical Studies

• In acute olanzapine poisoning cases, bradycardia occurred in a significant minority of patients, alongside the more common tachycardia (85%), demonstrating that olanzapine can produce opposing cardiovascular effects 2.
• A case report documented hypotension and bradycardia in a healthy volunteer following a single 5 mg dose of olanzapine, with rapid drug absorption and higher than anticipated plasma concentrations 3.
• ECG abnormalities in acute olanzapine poisoning include sinus bradycardia (4% of cases), though sinus tachycardia (22%) was more common 4.

Clinical Decision Algorithm

Step 1: Assess Hemodynamic Stability

First, determine if the bradycardia (HR 49) is causing hemodynamic compromise:

• Signs of instability include altered mental status, ischemic chest discomfort, acute heart failure, hypotension, or other signs of shock 5, 6.
• If the patient is hemodynamically unstable, olanzapine is contraindicated until the bradycardia is treated and stabilized.

Step 2: Treat Bradycardia Before Considering Olanzapine

If bradycardia is symptomatic or causing instability, initiate treatment per ACLS guidelines:

• Administer atropine 0.5-1 mg IV as first-line treatment, repeating every 3-5 minutes up to maximum 3 mg 5, 6.
• If unresponsive to atropine, initiate IV infusion of β-adrenergic agonists (dopamine 5-10 mcg/kg/min or epinephrine 2-10 mcg/min) or transcutaneous pacing 5, 6.

Step 3: Consider Alternative Antipsychotic Options

If acute agitation requires immediate treatment while bradycardia is present:

• Consider alternative antipsychotics with lower cardiovascular risk profiles.
• Intramuscular haloperidol may be preferable, though it also carries some cardiovascular risk 5.
• Avoid olanzapine until heart rate is stabilized above 60 bpm and hemodynamic parameters are normal.

Specific Contraindications and Warnings

The FDA label states olanzapine should be used with particular caution in patients with:

• Known cardiovascular disease (history of myocardial infarction or ischemia, heart failure, or conduction abnormalities) 1.
• Conditions predisposing to hypotension (dehydration, hypovolemia, antihypertensive medications) where syncope, hypotension, and/or bradycardia might put the patient at increased medical risk 1.

The risk for hypotension, bradycardia, and sinus pause may be greater in non-psychiatric patients compared to psychiatric patients who are possibly more adapted to certain effects of psychotropic drugs 1.

Critical Pitfalls to Avoid

• Never administer olanzapine to a patient with symptomatic bradycardia without first stabilizing the heart rate 1.
• Do not combine intramuscular olanzapine with parenteral benzodiazepines due to potential for excessive sedation and cardiorespiratory depression 1.
• Avoid using olanzapine in patients receiving other medications that can induce hypotension, bradycardia, or CNS depression without careful monitoring 1.
• For intramuscular olanzapine, patients should remain recumbent if drowsy or dizzy after injection until examination indicates they are not experiencing postural hypotension, bradycardia, and/or hypoventilation 1.

Monitoring Requirements If Olanzapine Must Be Used

If olanzapine is deemed absolutely necessary after bradycardia treatment and stabilization:

• Initiate with the lowest possible dose (5 mg PO daily for oral formulation) 1.
• Implement continuous cardiac monitoring for at least the first 24 hours 4.
• Monitor blood pressure, heart rate, and rhythm frequently 1.
• Keep atropine and transcutaneous pacing immediately available 6.
• Ensure patient remains recumbent or closely supervised for several hours after administration 1.