Effect of sildenafil citrate (Viagra) on erectile dysfunction in a patient with familial amyloidotic polyneuropathy ATTR Val30Met

A 34-year-old male patient with familial amyloidotic polyneuropathy (FAP) amyloidogenic transthyretin (ATTR) Valine30Methionine (Val30Met), who underwent a liver transplantation in Sweden in 1994, was treated with sildenafil citrate (Viagra) to ameliorate his erectile dysfunction (ED). Some clinical symptoms and the examination data for autonomic functions were improved after liver transplantation, but ED was never improved after the operation. Five years after liver transplantation, he requested a sildenafil citrate therapy to enhance his erectile potential. One and a half hours after the administration of 25 mg of sildenafil citrate, the skin surface temperature around the pelvic area increased and the penis became erect, though the postdose hemodynamic parameters did not significantly change from the respective baseline or predose values. He was able to have sexual intercourse, though ejaculation did not occur. This case report appears to suggest that sildenafil citrate is an effective drug to treat ED in patients with an organic impairment of the autonomic nervous system without altering systemic circulation.