Can Mounjaro (tirzepatide) cause tachycardia (increased heart rate)?

Tirzepatide (Mounjaro) and Increased Heart Rate

Yes, tirzepatide (Mounjaro) can cause increased heart rate (tachycardia) as a potential side effect, though it is not among the most commonly reported adverse effects.

Mechanism and Risk Factors

Tirzepatide is a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist used for type 2 diabetes management. While the medication's primary effects are on glucose control and weight reduction, it can affect cardiovascular parameters including heart rate.

The potential mechanisms for increased heart rate may include:

• Direct or indirect effects on the autonomic nervous system
• Metabolic changes that influence cardiac function
• Compensatory responses to other cardiovascular effects

Clinical Evidence and Considerations

The available evidence on tirzepatide's cardiovascular effects is still evolving. Current clinical trials have not highlighted tachycardia as a major concern, but cardiovascular effects warrant attention:

• The SURPASS clinical trials assessed tirzepatide's efficacy and safety but did not specifically highlight tachycardia as a common adverse effect 1, 2
• The ongoing SURPASS-CVOT study is specifically evaluating cardiovascular outcomes with tirzepatide compared to dulaglutide, which will provide more definitive evidence about cardiovascular effects 3

Management Recommendations

If a patient on tirzepatide experiences tachycardia:

1. Evaluate the severity and associated symptoms:

   • Determine if the tachycardia is persistent or intermittent
   • Assess for symptoms like palpitations, dizziness, chest discomfort, or shortness of breath
   • Check vital signs including blood pressure

2. Consider potential contributing factors:

   • Recent dose increases
   • Dehydration (especially if experiencing GI side effects like nausea or diarrhea)
   • Concurrent medications that may affect heart rate
   • Underlying cardiovascular conditions

3. Management options:

   • For mild, asymptomatic tachycardia: Monitor and reassess at follow-up
   • For moderate tachycardia: Consider dose reduction
   • For severe or symptomatic tachycardia: Temporarily discontinue tirzepatide and consider alternative therapies

4. If pharmacologic management of tachycardia is needed:

   • Beta-blockers (e.g., metoprolol) may be considered for persistent tachycardia if not contraindicated 4
   • Non-dihydropyridine calcium channel blockers (e.g., diltiazem, verapamil) are alternatives if beta-blockers are contraindicated 5

Precautions and Monitoring

• Baseline assessment: Evaluate cardiovascular status before initiating tirzepatide
• Regular monitoring: Check heart rate and blood pressure at follow-up visits
• High-risk patients: Use with caution in patients with pre-existing cardiovascular disease, arrhythmias, or conduction disorders
• Drug interactions: Be aware of potential interactions with medications that affect heart rate, including:
  • Anti-arrhythmic drugs
  • Beta-blockers
  • Calcium channel blockers
  • Sympathomimetic drugs 5

When to Refer to Cardiology

Consider cardiology referral if:

• Heart rate consistently >100 bpm despite dose adjustment
• New-onset arrhythmias develop
• Patient has significant cardiovascular disease and persistent tachycardia
• ECG shows abnormalities beyond simple sinus tachycardia

Key Takeaway

While tirzepatide can cause increased heart rate in some patients, this effect must be balanced against the medication's benefits for glycemic control and weight reduction. Careful monitoring and appropriate dose adjustments can help manage this side effect in most patients.