Can Tambacor (flecainide) cause hypotension?

Flecainide (Tambacor) and Hypotension

Yes, flecainide (Tambacor) can cause hypotension, particularly when administered intravenously or in patients with compromised cardiac function.

Mechanism and Evidence

Flecainide is a Class IC antiarrhythmic agent primarily used for treating supraventricular arrhythmias and ventricular tachycardia. The drug's negative inotropic effects contribute to its potential to cause hypotension:

• Clinical studies demonstrate that intravenous flecainide administration can decrease cardiac index by 8-12% and reduce left ventricular ejection fraction by 15-16% 1, 2
• These negative inotropic effects lead to increased pulmonary capillary wedge pressure (by 27-44%) and decreased stroke volume 3
• The FDA drug label specifically mentions hypotension as a potential adverse effect, particularly with rapid infusion 4

Risk Factors for Flecainide-Induced Hypotension

Certain patient populations are at higher risk for developing hypotension with flecainide:

1. Compromised cardiac function:

   • Patients with heart failure or reduced ejection fraction
   • Those with coronary artery disease 1, 2

2. Administration route and speed:

   • Intravenous administration carries higher risk than oral dosing
   • Rapid IV infusion increases hypotension risk 4

3. Renal impairment:

   • Patients with kidney dysfunction may experience drug accumulation
   • Dialysis patients are particularly vulnerable 5

4. Concomitant medications:

   • Combined use with other negative inotropic agents
   • Beta-blockers or calcium channel blockers may potentiate hypotensive effects 6

Clinical Implications and Management

When prescribing flecainide, consider these precautions:

• Baseline assessment: Evaluate cardiac function before initiating therapy
• Monitoring: Regular blood pressure monitoring is essential, especially during initiation
• Dose adjustment: Lower doses may be needed in patients with heart failure or renal impairment
• Administration: If using IV formulation, administer slowly over recommended time period
• Combination therapy: Use caution when combining with other medications that may cause hypotension 6

Special Considerations

In the emergency setting, flecainide-induced hypotension requires prompt recognition:

• Sodium bicarbonate administration may help reverse QRS widening and improve hemodynamics
• Avoid lidocaine and procainamide in suspected flecainide toxicity as they may worsen sodium channel blockade
• In severe cases, intralipid emulsion therapy or ECMO may be considered 5

For patients with atrial fibrillation requiring cardioversion, the risk of hypotension should be weighed against benefits, with one study reporting hypotension (systolic BP <90 mmHg) in approximately 4% of patients receiving IV flecainide 7.