I lost my wife to cancer a year ago. I have taken Imdur for 8 years(30 mg. once a day), have had occasional ED. asked my cardiologist about Cialis(I have not had any angina pain in years, and I exercise regularly). Since they are not compatible, he stopped Imdur and put me on 5 mg Cialis once daily(It does work well for the ED). When I saw how expensive Cialis is, I knew I could not afford it daily. My question is(I do have a lady friend, I might see her every week or two). I only need Cialis occasionally, is it ok to switch back and forth between imdur and cialis(say 1 cialis tab once every weekend, as long as I stop the cialis 2 days before going back to imdur and vice versa. Would it be safe to do so? I think I feel better overall when I am on the imdur, I only need the Cialis on occasion, and it is very expensive. They are both vasodilators, why could you not alternate occasionally as long as you stop a day or 2 before you start the other? Has anyone had a similar request or experience?