[brasarehot]

For example, hydrolysis of Amikacin. Here's a picture of it "http://mtnviewfarm.net/drugs-poisons-0080.html".
I know usual hydrolysis results in O=C-OH + NH2-R, but what does full protonation look like in acidic conditions?
Does NH2-R becomes R-NH3+? Do all the NH2's in the molecule become NH3+? Does anything else get extra hydrogens?

[fledarmus]

Putting this in an acid will protonate all the basic amine groups - the NH₂s.

Hydrolyzing amides requires more forcing conditions which will probably also break all the acetals that are present.