If you use other medicines, you may need to be closely monitored as the effects of Yondelis might be decreased (examples are medicines containing rifampicin (for bacterial infections), phenobarbital (for epilepsy) or St. John´s Wort (Hypericum perforatum, herbal medicine for depression)) or increased (examples are medicines containing ketoconazole or fluconazole (for fungal infections), ritonavir (for HIV infection), clarithromycin (for bacterial infections), ciclosporin (inhibit the defensive system of the body) or verapamil (for high blood pressure and heart conditions)) as a result.