Desuden har in vitro- forsøg med rotter og hepatocytter fra mennesker vist, at ambrisentan hverken hæmmer natriumtaurocholat co- transporter (NTCP), organisk anion eksportpumpe (OATP), galdesalteksportpumpe (BSEP) eller multistofresistensproteinisoform- 2 (MRP2).
Additional in vitro studies in rat and human hepatocytes showed that ambrisentan did not inhibit sodium-taurocholate co-transporter (NTCP), organic anion export pump (OATP), bile salt export pump (BSEP) and multi-drug resistance protein isoform-2 (MRP2).