Can a patient with a history of Coronary Artery Bypass Graft (CABG) take Viagra (sildenafil)?

Viagra Use After CABG: Safety Considerations and Recommendations

Patients with a history of CABG can safely take Viagra (sildenafil) as long as they are not using nitrate medications, which is an absolute contraindication due to risk of severe hypotension.

Safety Assessment Algorithm

1. Nitrate Medication Check

   • Absolute contraindication: Patients taking any form of nitrates (nitroglycerin, isosorbide mononitrate/dinitrate) CANNOT take sildenafil 1
   • The combination can cause severe, potentially fatal hypotension
   • If on long-acting nitrates, they must be discontinued before considering sildenafil

2. Cardiovascular Stability Assessment

   • Ensure patient is:
     • Hemodynamically stable
     • Free from unstable angina
     • At least 6-8 weeks post-CABG surgery (when sternotomy is well-healed) 1
     • Not within 6 months of acute MI or stroke 2

3. Exercise Capacity Evaluation

   • Sexual activity requires 3-5 METs (metabolic equivalents) of exertion 1, 3
   • Patient should be able to:
     • Climb two flights of stairs or
     • Walk briskly for 6 minutes without symptoms
     • Complete cardiac rehabilitation if possible 1

Clinical Considerations

Benefits

• Improved quality of life and psychological well-being
• Sexual dysfunction is common after CABG and addressing it is important for recovery 1
• Sildenafil has been shown to be safe in patients with stable coronary artery disease who are not on nitrates 3, 2

Hemodynamic Effects

• Sildenafil causes modest blood pressure reduction (approximately 8/6 mmHg) 4
• No significant changes in heart rate or cardiac output at therapeutic doses 4
• May actually improve coronary flow reserve in some patients with coronary artery disease 5

Risk Stratification

• Low risk: Asymptomatic, completed cardiac rehabilitation, good functional capacity
• Intermediate risk: Controlled symptoms, moderate functional capacity
• High risk (avoid sildenafil): Unstable angina, uncontrolled hypertension, severe heart failure, recent MI/stroke

Important Precautions

• Start with lowest effective dose (25mg) in post-CABG patients
• Educate patient about potential side effects: headache, flushing, dyspepsia
• Emergency protocol: If chest pain occurs during sexual activity:
  • Stop activity immediately
  • If taking sildenafil, DO NOT take nitroglycerin for at least 24 hours (48 hours for tadalafil) 1
  • Call emergency services if chest pain persists >15 minutes 1

Common Pitfalls to Avoid

1. Nitrate interaction: Never prescribe sildenafil to patients using any form of nitrates
2. Inadequate risk assessment: Failing to assess exercise capacity before recommending sildenafil
3. Ignoring timing: Prescribing too soon after CABG (before adequate healing)
4. Medication reconciliation errors: Not checking for drug interactions with other post-CABG medications
5. Inadequate patient education: Not informing about emergency protocols if chest pain occurs

Sildenafil can be a safe and effective treatment for erectile dysfunction in most post-CABG patients who are stable, not taking nitrates, and have adequate exercise capacity. The benefits to quality of life often outweigh the small cardiovascular risks in appropriately selected patients.