Forsigtighed tilrådes dog ved CYP2D6- substrater med et snævert terapeutisk vindue som f. eks. metorpolol.
Dose adjustments do not seem to be necessary when imatinib is co-administrated with CYP2D6 substrates, however caution is advised for CYP2D6 substrates with a narrow therapeutic window such as metoprolol.