Drug | Dose | Half-life (duration of action) | Potential adverse effects |
---|---|---|---|
Intravenous | Â | Â | Â |
   Prostacyclin (Epoprostenol, Flolan) | Start at 1 ng/kg/min; titrate upward in 2-ng/kg/min increments according to effect | 3-5 minutes (10 minutes) | Systemic hypotension, worsening oxygenation (increased V/Q mismatch), antiplatelet effect, headache, flushing, jaw pain, nausea, diarrhea |
   Iloprost | 1-5 ng/kg/min | 30 minutes | Similar to Flolan; also syncope (5%) |
   Sildenafil [325] (NB off-license use in hemodynamically unstable patients) | Low dose, 0.05 mg/kg; high dose, 0.43 mg/kg) (comes as 0.8 mg/ml) | 3-5 hours | Hypotension: caution if fluid depleted, severe LV-outflow obstruction, autonomic dysfunction. Hypoxemia due to V/Q mismatch. Common: headache, flushing, diarrhea, epistaxis, tremor. Rare but important: anterior ischemic optic neuropathy |
   Milrinone | 50 μg/kg over 10 minutes followed by 0.375-0.75 μg/kg/min infusion | 1-2 hours | Tachyarrhythmias, hypotension |
   Adenosine | 50-350 μg/kg/min, titrate up in 50 μg/kg/min increments | 5-10 seconds (2 minutes) | Bradycardia, bronchospasm, chest pain |
Inhaled (preferred; Note variable absorption likely) | Â | Â | Â |
0.2-0.3 ml/min of 10-20 μg/ml nebulized into inspiratory limb of ventilator circuit (30-40 ng/kg/min) | 3-5 minutes | As above but less hypotension and improved oxygenation compared with intravenous use | |
   Iloprost [275] | 2.5-5 μg 6-9 times/day, 1 mg/ml milrinone into the ventilator circuit at 0.2-0.3 ml/min for 10-20 minutes | 30 minutes | As above and bronchospasm |
5-80 ppm continuously | 1-2 hours | Less systemic hypotension than with IV milrinone | |
   NO |  | 15-30 seconds (5 minutes) | Methemoglobinemia; withdrawal PH |
ORAL (rarely in ICU) | Â | Â | Â |
   Bosentan | 62.5-125 mg b.d. | 5 hours | Liver-function test abnormalities; drug interactions; edema |
   Sildenafil | 0.25-0.75 mg/kg 4 hrly | 3-4 hours | As above; less hypotension and hypoxemia in stable patients |