Do not take senna without medical advice if you are using any of the following medications:
birth control pills or hormone replacement therapy;
digoxin (Lanoxin);
a diuretic (water pill); or
warfarin (Coumadin, Jantoven).
This list is not complete. Other drugs may affect senna, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.
 Senokot drug interactions (more detail)
