United Therapeutics Corporation markets four medicines in the United States to treat pulmonary arterial hypertension (PAH): Remodulin, an injectable formulation of treprostinil, Orenitram, an oral version of treprostinil, Tyvaso, an inhaled version of treprostinil, and Adcirca (tadalafil; also sold by Eli Lilly as Cialis for erectile dysfunction) tablets.