Is thioctic acid the same as alpha lipoic acid?
Yes, it is the same compound under a different name.
Should I take it with food?
Most people do. Follow the amount on the pack.
Which strength should I buy?
Compare cost per capsule at the strength you want rather than the price of the pot, since counts vary a lot.
Can I take it with prescribed medication?
Ask your pharmacist first. This is one genuinely worth checking rather than assuming.