I was diagnosed with liver disease May of 2012. In August 2012 I was diagnosed with PN. When the Neurologist told me, I asked her what the treatment was and she abruptly told me there was none! Well, I didn't take her word for it, so after I had a good cry, and my own little pity party, I decided to research it, and educate myself. I found this forum and started reading. I'm taking the following meds and supplements.
Gabapentin 300mg 3x daily.
Spironolactone 50mg 1x daily.
Furosemide 20mg 1x daily.
Multivitamin.
Vitamin D 4000
Calcium 500mg
Magnesium 500mg
B12 1000mg

Furosemide will deplete magnesium and thiamine B1.
Make sure your magnesium is not an oxide form. It is best to use a chelate or SlowMag orally.

The B12 needs to be taken on an empty stomach for best absorption results.

There is another poster here who believes their PN was from spironolactone use.

Some people with liver problems use milk thistle to help that.
Also NAC (n-acetyl cysteine) 600mg 2 or 3 times a day may help if it is drug induced damage. ( like from excessive Tylenol consumption).

more on NAC here:
http://www.webmd.com/vitamins-supple...TYL%20CYSTEINE