PAH Overview

PAH is a rare, life-threatening disease in which chronically elevated pressure in the pulmonary arteries causes progressive strain—and ultimately failure—of the right ventricle of the heart.¹ PAH causes narrowing of the smallest pulmonary arteries, elevating blood pressure within them to dangerously high levels.² Survival among untreated or inadequately treated patients with PAH is typically less than 5 years after diagnosis.³

PAH is defined by a mean pulmonary artery pressure at rest ≥25 mm Hg in the presence of a pulmonary capillary wedge pressure ≤15 mm Hg. To eliminate the confounding effects of cardiac output and left ventricular end-diastolic pressure, pulmonary vascular resistance >3 Wood units should also be present.⁴

PAH Pathogenesis (MOD)

Selected Important Safety Information

The most common adverse events seen with Tyvaso in ≥4% of PAH patients and more than 3% greater than placebo in the placebo-controlled clinical study were cough (54% vs 29%), headache (41% vs 23%), throat irritation/pharyngolaryngeal pain (25% vs 14%), nausea (19% vs 11%), flushing (15% vs <1%), and syncope (6% vs <1%)
Tyvaso should be used in pregnancy only if clearly needed. Caution should be exercised when Tyvaso is administered to nursing women

Indication

Tyvaso is a prostacyclin vasodilator indicated for the treatment of pulmonary arterial hypertension (PAH) (WHO Group 1) to improve exercise ability. Studies establishing effectiveness included predominately patients with NYHA Functional Class III symptoms and etiologies of idiopathic or heritable PAH (56%) or PAH associated with connective tissue diseases (33%).

The effects diminish over the minimum recommended dosing interval of 4 hours; treatment timing can be adjusted for planned activities.

While there are long-term data on use of treprostinil by other routes of administration, nearly all controlled clinical experience with inhaled treprostinil has been on a background of bosentan (an endothelin receptor antagonist) or sildenafil (a phosphodiesterase type 5 inhibitor). The controlled clinical experience was limited to 12 weeks in duration.

Important Safety Information for Tyvaso

Tyvaso is intended for oral inhalation only. Tyvaso is approved for use only with the Tyvaso Inhalation System
The safety and efficacy of Tyvaso have not been established in patients with significant underlying lung disease (such as asthma or chronic obstructive pulmonary disease) and in patients under 18 years of age. Patients with acute pulmonary infections should be carefully monitored to detect any worsening of lung disease and loss of drug effect
Tyvaso may increase the risk of bleeding, particularly in patients receiving anticoagulants
In patients with low systemic arterial pressure, Tyvaso may cause symptomatic hypotension. The concomitant use of Tyvaso with diuretics, antihypertensives, or other vasodilators may increase the risk of symptomatic hypotension
Hepatic or renal insufficiency may increase exposure to Tyvaso and decrease tolerability. Tyvaso dosage adjustments may be necessary if inhibitors of CYP2C8 such as gemfibrozil or inducers such as rifampin are added or withdrawn
The most common adverse events seen with Tyvaso in ≥4% of PAH patients and more than 3% greater than placebo in the placebo-controlled clinical study were cough (54% vs 29%), headache (41% vs 23%), throat irritation/pharyngolaryngeal pain (25% vs 14%), nausea (19% vs 11%), flushing (15% vs <1%), and syncope (6% vs <1%)
Tyvaso should be used in pregnancy only if clearly needed. Caution should be exercised when Tyvaso is administered to nursing women

For more information about Tyvaso, please see the Full Prescribing Information, Patient Package Insert, and the Tyvaso Inhalation System Instructions for Use Manual. Questions? Call the Customer Service Line at 1-877-UNITHER (1-877-864-8437).

1.	National Organization for Rare Disorders. Pulmonary hypertension, primary. http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/706/viewAbstract. Accessed July 11, 2011.
2.	Badesch DB, Abman SH, Simonneau G, Rubin LJ, McLaughlin VV. Medical therapy for pulmonary arterial hypertension: updated ACCP Evidence-Based Clinical Practice Guidelines. Chest. 2007;131:1917-1928.
3.	Newman JH, Phillips JA III, Loyd JE. Narrative review: the enigma of pulmonary arterial hypertension: new insights from genetic studies. Ann Intern Med. 2008;148:278-283.
4.	McLaughlin VV, Archer SL, Badesch DB, et al.. ACCF/AHA 2009 expert consensus document on pulmonary hypertension: a report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents and the American Heart Association: developed in collaboration with the American College of Chest Physicians, American Thoracic Society, Inc., and the Pulmonary Hypertension Association. Circulation. 2009;119(16):2250-94.