Favorable effects of inhaled treprostinil in severe pulmonary hypertension: results from randomized controlled pilot studies

J Am Coll Cardiol. 2006 Oct 17;48(8):1672-81. doi: 10.1016/j.jacc.2006.06.062. Epub 2006 Sep 26.


Objectives: This study sought to investigate the effects of inhaled treprostinil on pulmonary hemodynamics and gas exchange in severe pulmonary hypertension.

Background: Inhaled iloprost therapy has a proven clinical efficacy in pulmonary arterial hypertension, but this therapy necessitates 6 to 9 inhalation sessions per day. Treprostinil has a longer plasma half-life and might provide favorable properties when applied by inhalation.

Methods: Three different studies were conducted on a total of 123 patients by means of right heart catheterization: 1) a randomized crossover-design study (44 patients), 2) a dose escalation study (31 patients), and 3) a study of reduction of inhalation time while keeping the dose fixed (48 patients). The primary end point was the change in pulmonary vascular resistance (PVR).

Results: The mean pulmonary arterial pressure of the enrolled patients was approximately 50 mm Hg in all studies. In study 1, both treprostinil and iloprost at an inhaled dose of 7.5 mug displayed a comparable PVR decrease, with a significantly different time course (p < 0.001), treprostinil showing a more sustained effect on PVR (p < 0.0001) and fewer systemic side effects. In study 2, effects of inhalation were observed for 3 h. A near-maximal acute PVR decrease was observed at 30 mug treprostinil. In study 3, treprostinil was inhaled at increasing concentrations with a pulsed ultrasonic nebulizer, mimicking a metered dose inhaler. A dose of 15 mug treprostinil was inhaled with 18, 9, 3, 2 pulses, or 1 pulse, each mode achieving comparable, sustained pulmonary vasodilation without significant side effects.

Conclusions: Inhaled treprostinil exerts sustained pulmonary vasodilation with excellent tolerability at relatively low doses and may be inhaled in a few breaths.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Inhalation
  • Blood Pressure
  • Cross-Over Studies
  • Dose-Response Relationship, Drug
  • Drug Administration Schedule
  • Epoprostenol / administration & dosage
  • Epoprostenol / analogs & derivatives*
  • Epoprostenol / blood
  • Epoprostenol / therapeutic use
  • Humans
  • Hypertension, Pulmonary / blood
  • Hypertension, Pulmonary / drug therapy*
  • Hypertension, Pulmonary / physiopathology*
  • Nebulizers and Vaporizers
  • Pilot Projects
  • Pulmonary Artery / physiopathology
  • Pulmonary Circulation / drug effects
  • Severity of Illness Index
  • Single-Blind Method
  • Ultrasonics
  • Vascular Resistance / drug effects
  • Vasodilation / drug effects


  • Epoprostenol
  • treprostinil