Tadalafil is a PDE5 inhibitor, currently marketed in pill form for treating erectile dysfunction (ED) under the name Cialis; it has recently been approved for the treatment of pulmonary arterial hypertension, and has been used for other conditions. It initially was developed by the biotechnology company ICOS, and then again developed and marketed world-wide by Lilly ICOS, LLC, the joint venture of ICOS Corporation and Eli Lilly and Company. Cialis tablets, in 5 mg, 10 mg, and 20 mg doses, are yellow, film-coated, and almond-shaped. The approved dose for pulmonary arterial hypertension is 40 mg, and is marketed under the brand name Adcirca.
In December 2002, the Food and Drug Administration approved tadalafil (as Cialis) for sale in the United States as the third ED prescription drug pill (after sildenafil citrate (Viagra) and vardenafil (Levitra)). Cialis's 36-hour effectiveness earned it the nickname, "The Weekend Pill"; like sildenafil and vardenafil, tadalafil is recommended as an 'as needed' medication. Cialis is the only one of the three that is also offered as a once-daily medication.
Moreover, tadalafil was approved in May 2009 in the United States for the treatment of pulmonary arterial hypertension and is currently under regulatory review in other regions for this condition. In late November 2008, Eli Lilly sold the exclusive rights to commercialize tadalafil for pulmonary arterial hypertension in the United States to United Therapeutics for an upfront payment of $150 million.