What are the initial medications used to treat constrictive pericarditis?

Initial Medications for Constrictive Pericarditis

The initial medical therapy for constrictive pericarditis should include diuretics (typically loop diuretics) for symptom management, with anti-inflammatory medications (NSAIDs, colchicine, and/or corticosteroids) added when there is evidence of active inflammation. 1, 2

Pathophysiology and Presentation

Constrictive pericarditis is characterized by impaired diastolic filling of the ventricles due to a thickened, fibrotic, and often calcified pericardium. Patients typically present with:

• Signs and symptoms of right heart failure (fatigue, peripheral edema, breathlessness, abdominal swelling)
• Venous congestion, hepatomegaly, pleural effusions, and ascites
• Preserved ventricular function in early stages 1

Medical Management Algorithm

First-Line Therapy (Symptomatic Management)

1. Loop diuretics (e.g., furosemide) - primary treatment to manage volume overload, edema, and congestive symptoms 2

   • Start with oral therapy, increasing to IV administration if resistance develops
   • Monitor for electrolyte imbalances and renal function

2. Salt restriction - to complement diuretic therapy

For Cases with Evidence of Active Inflammation

When there are signs of ongoing inflammation (elevated CRP, contrast enhancement on CT/CMR), add:

1. NSAIDs/Aspirin (high doses) 3

   • Aspirin: 1500-3000 mg/day
   • Ibuprofen: 1200-2400 mg/day
   • Indomethacin: 75-150 mg/day

2. Colchicine 3

   • 0.5mg twice daily for patients ≥70kg
   • 0.5mg daily for patients <70kg
   • Continue for at least 3-6 months

3. Corticosteroids (second-line, if NSAIDs/colchicine are ineffective or contraindicated) 1, 3

   • Low-dose (0.25-0.50 mg/kg/day)
   • Taper gradually according to clinical response
   • For doses >50 mg: reduce by 10 mg/day every 1-2 weeks
   • For doses 50-25 mg: reduce by 5-10 mg/day every 1-2 weeks
   • For doses 25-15 mg: reduce by 2.5 mg/day every 2-4 weeks
   • For doses <15 mg: reduce by 1.25-2.5 mg/day every 2-6 weeks

Special Considerations for Specific Etiologies

1. Tuberculous pericarditis 1

   • Antituberculosis therapy (rifampicin, isoniazid, pyrazinamide, and ethambutol) for at least 6 months
   • Consider adjunctive corticosteroids to reduce risk of progression to constriction
   • Note: Appropriate TB treatment can reduce constriction risk from >80% to <10%

2. Bacterial pericarditis 3

   • Targeted antibiotics based on culture results
   • Consider drainage if purulent

Monitoring and Follow-up

1. Regular echocardiographic assessment to evaluate:

   • Pericardial thickness
   • Ventricular filling patterns
   • Development of tamponade

2. Inflammatory markers (CRP, ESR) to guide treatment duration 3

3. Rhythm monitoring - treat atrial arrhythmias aggressively as they can worsen heart failure symptoms 4

Important Caveats

1. Transient vs. Permanent Constriction: In 10-20% of cases, constriction may be transient and resolve with anti-inflammatory therapy, particularly when there is evidence of ongoing inflammation 1, 5

2. Definitive Treatment: Medical therapy is generally supportive and temporary. Pericardiectomy remains the only definitive treatment for chronic constrictive pericarditis 1, 2, 5

3. Timing of Surgery: Medical therapy should not unnecessarily delay surgical intervention in advanced cases, as delayed surgery is associated with worse outcomes 1

4. Refractory Cases: For patients with multiple recurrences or steroid-dependent disease, consider IL-1 blockers like anakinra (2 mg/kg/day up to 100 mg SC) or rilonacept (loading dose 320 mg SC, then 160 mg weekly) 3, 6

Medical therapy plays a crucial role in managing symptoms and potentially reversing constriction in its early inflammatory phase, but clinicians should maintain a low threshold for referral to pericardiectomy when patients show persistent symptoms despite optimal medical management.