Are you talking about nucleophillic ACYL substitution?
If so, yes, amides are the second LEAST reactive of the carboxylic acid derivatives. Nitriles are the least reactive.
acyl chlorides/bromides > anhydride ~ acid > ester > amide > nitrile is the order of reactivity.
Part of the reason for the amide's unreactivity towards nucleophillic acyl substitution has to do with the nitrogens electron donating RESONANCE effect. Empirically, we see that a carbon nitrogen bond with s character (it's closer to sp2 than sp3 thus the bond has partial double bonding character).
This makes the carbonyl less electrophillic and therefore less reactive.