Table 6.

Intra-class oral PAH medication transitions: endothelin receptor antagonists.

No.	Original drug	Drug transitioned to	Publication year	Study	PAH patients	Time	Measures	Outcome
1	Bosentan or sitaxsentan	Ambrisentan	2009 / McGoon et al.25	Prospective open-label	36 (prior abnormal LFTs with therapy)	12 weeks	LFTs > 3x’s ULN; Tx discontinuation, Δ in 6MWD) Borg dyspnea index, WHO FC functional class, health survey score	One out of 36 with LFTs > 3x’s ULN; no discontinuations; improvements in other clinical endpoints

LFT, liver function tests; ULN, upper limit of normal.