OBJECTIVES: Estimate annual utilization and cost of prostacyclins (PGI2) among patients with pulmonary arterial hypertension (PAH). METHODS: Truven^® Commercial and Medicare Databases were used to identify annual cohorts of adults with PAH (i.e., International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes [416.0 or 416.8] and ≥1 claims for PAH-specific medications) between calendar-year (CY) 2010 and CY2014. Patients with ≥1 claims for PGI2 were deemed PGI2 users. PGI2 use was categorized as parenteral vs. non-parenteral.  PAH-related included costs of PAH-specific medications and all medical claims with a relevant diagnosis code.  RESULTS: A total of 12,306 patients met selection criteria for at least 1 CY of the study period. Annual prevalence of PGI2 use ranged from 20% to 22%. Among PGI2 users, treprostinil use increased from 50% in CY2010 to 71% in CY2014; corresponding decreases for epoprostenol and iloprost were 31% to 22% and 26% to 10%, respectively. Use of other PAH-specific medication among PGI2 users increased over time, from 62% in CY2010 to 69% in CY2014. Mean (standard deviation [SD]) annualized PGI2 costs ranged from $99,919 ($100,139) to $118,861 ($136,493) per CY. Use of parenteral PGI2 decreased over time (from 63.2% in CY2010 to 52.4% in CY2014), whereas non-parenteral PGI2 usage increased (from 39.7% to 49.5%). Other PAH-specific medications were used in the same CY for 74.1%–77.6% of non-parenteral PGI2 users, compared to 54.4%–64.3% of parenteral PGI2 users. Mean parenteral PGI2 costs in CY2010 were twice those of non-parenteral PGI2. By CY2014, parenteral PGI2 costs were 8% lower than non-parenteral costs. Mean (SD) PAH-related costs ranged from $189,763 ($167,329) during CY2010 to $199,336 ($194,638) during CY2013. CONCLUSIONS: While overall use of PGI2 was constant over the five-year period, our findings suggest a shift towards non-parenteral PGI2 and PGI2 combination therapy in clinical practice.