CALCIUM-CHANNEL BLOCKERS AND DARIFENACIN
Erythromycin almost doubles the AUC of darifenacin by inhibiting its metabolism by CYP3A4. Other moderate inhibitors of CYP3A4, such as diltiazem and verapamil are expected to interact similarly.
The US manufacturers suggests that no dosage adjustments are necessary with these calcium-channel blockers, whereas the UK manufacturer suggests increasing the darifenacin dose with caution. Bear in mind the possibility of an interaction if antimuscarinic effects (dry mouth, constipation, drowsiness) are increased.
The US manufacturers suggests that no dosage adjustments are necessary with these calcium-channel blockers, whereas the UK manufacturer suggests increasing the darifenacin dose with caution. Bear in mind the possibility of an interaction if antimuscarinic effects (dry mouth, constipation, drowsiness) are increased.