What is the recommended dose of sildenafil (Revatio) for intravenous (IV) infusion in patients with pulmonary arterial hypertension?

Sildenafil IV Infusion Dosing for Pulmonary Arterial Hypertension

For adult patients with pulmonary arterial hypertension (PAH), the recommended intravenous (IV) sildenafil dosing is 10 mg administered as a continuous infusion over 3 hours every 8 hours, which can be titrated based on clinical response and hemodynamic parameters.

Background and Evidence

Sildenafil is a phosphodiesterase type 5 (PDE-5) inhibitor that has been shown to be effective in the treatment of PAH. While oral sildenafil is more commonly used, IV administration may be necessary in certain clinical scenarios such as:

• Patients unable to take oral medications
• Perioperative management of PAH
• Acute decompensation of PAH
• Patients with limited venous access requiring intermittent dosing

Dosing Considerations

Adult Dosing

• Initial dose: 10 mg IV administered over 3 hours every 8 hours 1
• This corresponds to the oral equivalent of 20 mg every 8 hours, which is the FDA-approved dose for PAH
• Titration: May be increased based on clinical response and tolerability

Pediatric Dosing

For completeness, pediatric dosing differs significantly:

• Age <1 year: 0.4-2 mg/kg every 6 hours 1, 2
• Infusion periods typically range from 1-3 hours 2
• Longer infusion periods (3 hours) are recommended to minimize hypotension risk

Monitoring and Safety Considerations

When administering IV sildenafil, careful monitoring is essential:

1. Hemodynamic monitoring:

   • Blood pressure (risk of systemic hypotension)
   • Pulmonary artery pressure
   • Cardiac output/index

2. Common adverse effects:

   • Headache
   • Flushing
   • Nasal congestion
   • Hypotension (particularly during initial dosing)

3. Important precautions:

   • Avoid concomitant use with nitrates (severe hypotension risk)
   • Use caution when combining with other vasodilators
   • Contraindicated with riociguat due to risk of severe hypotension 1

Clinical Efficacy

IV sildenafil has demonstrated several beneficial effects in PAH:

• Significant decrease in pulmonary artery pressure
• Increase in cardiac index
• Reduction in pulmonary vascular resistance
• Improvement in functional capacity 3

Practical Administration Tips

• Ensure proper dilution according to institutional protocols
• Administer through a dedicated line or port when possible
• Monitor vital signs closely during initial administration
• Consider gradual weaning rather than abrupt discontinuation to prevent potential rebound pulmonary hypertension 2

Transitioning to Oral Therapy

Once the patient can tolerate oral medications, transition to oral sildenafil at 20 mg three times daily is recommended 1. This maintains the therapeutic effect while allowing for easier long-term administration.

In summary, IV sildenafil represents an important therapeutic option for PAH patients unable to take oral medications, with dosing of 10 mg administered over 3 hours every 8 hours being the standard approach for adults, with careful monitoring of hemodynamic parameters.