I'm in an HMO so can only get the lidocaine ointment. A few years ago my neurologist told me when I put the ointment on my feet cover them with plastic wrap for an hour and then wash it off. Reasoning was otherwise the ointment evaporates too quickly. Has anyone heard of this being done?

Covering a medication with saran wrap forces the drug deeper into the tissues. Any drug. The product EMLA was done this way, prior to
minor surgery of the skin or needle sticks for children.

The differences between Lidoderm and the ointment with saran wrap is that the patch delivers the lidocaine constantly, whereas the ointment may not. So duration may be shorter.

Lidoderms are 5%, and lidocaine ointments vary between
2 and 5% in strength.

There is an oral drug that works in a similar fashion, called
Mexitil.
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000413/
Some doctors won't give it though because of its side effect profile which is serious.

Lidocaine is part of a drug family called sodium ion channel
blockers.

This article explains, and gives names to other oral drugs:
http://en.wikipedia.org/wiki/Sodium_channel_blocker