Research
Because of preliminary data suggesting the drug may have activity, the U.S. FDA has granted tolcapone "orphan drug status" in studies aiming at the treatment of familial transthyretin amyloidosis (ATTR). However, tolcapone is not FDA approved for the treatment of this disease. References
External links
"Tolcapone". Drug Information Portal. U.S. National Library of Medicine.
Most cases are marked by asymmetric polyneuropathy, but progressive disease can lead to symmetric nerve involvement. Central nervous system involvement may cause strokes or seizures.Renal system: Kidney involvement is common and often leads to death of parts of the kidney. Involvement of the renal artery, which supplies the kidneys with highly oxygenated blood, often leads to high blood pressure in about one-third of cases. deposition of protein or blood in the urine may also be seen. Almost all patients with PAN have renal insufficiency caused by renal artery narrowing, thrombosis, and infarctions. Cardiovascular system: Involvement of the arteries of the heart may cause a heart attack, heart failure, and inflammation of the sac around the heart (pericarditis).Gastrointestinal system: Damage to mesenteric arteries can cause abdominal pain, mesenteric ischemia, and bowel perforation. Abdominal pain may also be seen. Musculoskeletal system: Muscle and joint aches are common. Complications
Stroke
Heart failure resulting from cardiomyopathy and pericarditis
Intestinal necrosis and perforation

Causes
PAN has no association with anti-neutrophil cytoplasmic antibodies, but about 30% of people with PAN have chronic hepatitis B and deposits containing HBsAg-HBsAb complexes in affected blood vessels, indicating an immune complex-mediated cause in that subset. Infection with the hepatitis C virus and HIV are occasionally discovered in people affected by PAN. PAN has also been associated with underlying hairy cell leukemia. The cause remains unknown in the remaining cases; there may be causal and clinical distinctions between classic idiopathic PAN, the cutaneous forms of PAN, and PAN associated with chronic hepatitis.