Labeling for this product contains a bolded warning at the BEGINNING of the package insert THAT IS NOT BOXED.
Do Not Interchange
Do not interchange Zaroxolyn tablets and other formulations of metolazone that share its slow and incomplete bioavailability and are NOT therapeutically equivalent at the same doses to Mykrox tablets, a more rapidly available and completely bioavailable metolazone product.
Formulations bioequivalent to Zaroxolyn and formulations bioequivalent to Mykrox should NOT be interchanged for one another.