intracellular action of terfenadine

[Sei Kobayashi]

I would like to know whether terfenadine (TF) could go through the cell
membrane. 

TF is commonly and frequently used for the treatment of allergic disorders. 
However, individual case reports showed that TF may cause a fatal or 
near-fatal cardiotoxic actions. 

Although TF is reported to affect some ion channels, I am thinking of the 
possibility of intracellular actions of TF. Would it be possible that TF may 
modulate some intracellular signal transduction systems? Any information 
would be greatly appreciated. E-mail replies welcome. 

Thank you in advance for your help.

Sincerely yours,

Sei Kobayashi
Division of Molecular Cardiology
Research Institute of Angiocardiology
Faculty of Medicine, Kyushu University, Japan