Class	Medication	Dosing	Adverse effects	Comments	Cost per unit*	Cost per day
Prostacyclin analogues	Epoprostenol (Flolan)	Commonly started in hospital at 2 ng per kg per minute by continuous intravenous infusion; typical dosing is around 15 ng per kg per minute; titration based on symptoms and adverse effects	Flushing, headache, skeletal pain, diarrhea Local infections (related to central venous catheter system) Abrupt interruption of treatment can lead to worsening of PAH	First medication shown to improve survival in idiopathic PAH21 Improves symptoms, exercise capacity, and hemodynamic measures22,23 Recommended for unstable patients in functional classes III and IV 6	$52 for 1.5-mg intravenous dose	$52, based on 15 ng per kg per minute for patient weighing 70 kg (154 lb)
	Iloprost (Ventavis)	Inhaled: 2.5 to 5.0 mcg taken six to nine times per day, but not more than once every two hours, via adaptive aerosol device Intravenous infusion: maintenance dosage of 2 to 4 ng per kg per minute Oral: 50 to 300 mcg twice per day	Cough (from inhaled formulation), flushing, headaches, insomnia, vomiting	Inhaled formulation shows small but statistically significant improvement of symptoms in patients with severe PAH24 Approved for patients in functional classes III and IV	$39 for 2-mL inhalation (10 mcg per mL)	$39, based on 2.5 mcg via inhaled formulation eight times per day
	Treprostinil (Remodulin)	Maintenance dosage typically around 15 ng per kg per minute via continuous subcutaneous or intravenous infusion	Similar to epoprostenol, including facial flushing, headache, jaw pain, nausea, diarrhea Infusion site pain occurs in 85 percent of patients; can lead to discontinuation of treatment in 8 percent of patients when administered via continuous transcutaneous system26 Increased risk of gram-negative bacteremia27	Improves exercise capacity; hemodynamics and survival similar to epoprostenol25 Approved for patients in functional classes II and III; intravenous use approved in patients who cannot tolerate subcutaneous infusion6	$1,345 for 20-mL multidose vial (1 mg per mL)	$100, based on 15 ng per kg per minute for patient weighing 70 kg
Endothelin receptor antagonists	Ambrisentan (Letairis)	5 to 10 mg orally once per day	Generally well tolerated Adverse effects generally unrelated to dose28 Peripheral edema mostly in patients older than 65 years28 Hepatic transaminase elevations occur at lower rate than with bosentan28	Prescribed only through the Letairis Education and Access Program Specific to endothelin A receptor Approved in the United States in 2007 for patients in functional classes II and III29,30 FDA requires liver function testing once per month and hematocrit testing every three months Contraindicated in pregnancy	$192 for 10-mg tablet	$192 for 10 mg per day
	Bosentan (Tracleer)	125 mg orally twice per day	Dose-dependent reversible elevations of hepatic transaminase levels in 10 percent of patients Anemia and edema can occur	Nonspecific endothelin receptor antagonist Improves hemodynamics, exercise capacity, and echocardiographic results; delays time to clinical worsening31–33 Approved for patients with symptomatic heart failure; benefits shown in patients in functional class II34 FDA requires liver function testing once per month and hematocrit testing every three months	$96 for 125-mg tablet	$192
	Sitaxsentan†	Dosages of 100 to 300 mg orally once per day are being studied	Appears similar to other medications in the class	Specific to endothelin A receptor Benefit and safety demonstrated,35 although currently not approved by the FDA	NA	NA
Phosphodiesterase type 5 inhibitors	Sildenafil (Revatio)	20 mg orally three times per day (FDA-approved for PAH treatment)	Headache, dyspepsia, flushing	Improves cardiopulmonary hemodynamics and exercise capacity36,37	$17 for 20-mg tablet	$51
	Tadalafil (Adcirca)	2.5 to 40 mg orally once per day (40 mg was needed for statistically significant effects38)	Headache, flushing, myalgias38	Slowed incidence of clinical worsening and improved six-minute walk test38 Approved in the United States in 2009 for patients in functional classes II and III	$19 for 20-mg tablet	$38 for 40 mg per day