Well, I think it is unusual to be on a low dose levothyroxine product after a TOTAL removal of the thyroid gland.
Usually they start people off at 100mcg to 125mcg.

Thank you for the quote... the grammar? Was this an abbreviated download? When I went there I saw that the abbreviated download was free but a charge for the full book?
If this quote is from the abbreviated one...I think what it is saying is that gabapentin has interactions, and among other drugs, there is levothyroxine (and maybe more with their own interactions). So the grammar is odd IMO in this quote.

Gabapentin is popular because it DOES NOT interact much with other drugs. It is not metabolized by the liver, and so all the enzyme effects on the liver are not present.
This is a further detail on drugchecker at drugs.com
only 5 major interactions
http://www.drugs.com/drug-interactio...&generic_only=

This is the moderate list which is longer:
http://www.drugs.com/drug-interactio...&generic_only=
While this list looks impressive, this interaction is mostly
for the sedative nature and side effects of potential cognitive impairment with gabapentin which are so common for most people.

Levothyroxine does not cause cognitive impairment or sleepiness so it is not on the moderate list either.

Now, one type of interaction with levothyroxine which is possible with some drugs, like warfarin, is the displacement off carrier proteins in the blood. Thyroid hormones are shipped around the body by these proteins and some drugs have more affinity for them than others. So the thyroid hormone may be bumped off its carrier by something else. But I don't see this listed from Drugchecker either. It is possible you are having problems with the proteins that carry drugs. Either you take another drug which is knocking the thyroid hormone off resulting in poor distribution, or your body is low in protein from diet or some other reason, and the hormone cannot be distributed well, because of that.

So with the added detail of your total removal of the gland, then the kelp/iodine suggestion would not work for you. That only works if some gland is present.

Yes, I have PN in my hands too. It was very acute at one time, and now is only minor. I control it with wearing carpal tunnel braces when needed. It tends to flare with fluid retention or overuse of my hands (computer, gardening, stressful tasks).

The type of PN that comes from HYPOthyroid conditions is mostly compressive in nature. Hypothyroid situations, result in the deposit of a type of tissue in the body, at the wrists and
ankles, and this compresses nerves and causes pain, numbness and/or loss of function. When I was pregnant the additional hormones created a severe compression at my wrists, and EMG showed 80% loss of function. This resolved to my old levels after I delivered my son.

By the time I was finally diagnosed, my feet were pretty numb.
During my titration up in dosage over the months, they "woke up" and tingled alot until most of the numbness is gone. I still have some residual numbness in the middle toes of each foot, but the doctor would not go higher with the levothyroxine because of my TSH at 1.5-2. It varies in that range now.