(2) Increased inactivation: e.g aldehyde dehydrogenase converse cyclophosphamide to inactive metabolite. (3) Altered nucleotide pools: Can occur with antimetabolites• (2) Increased inactivation: e.g., aldehyde dehydrogenase converse cyclophosphamide to inactive metabolite. • (3) Altered nucleotide pools: Can occur with antimetabolites