How do doctors view drug interactions?

I thought I’d share an interesting experience I had recently. Recently my dad was ill and so I went to visit him in California. Now that I am in pharmacy school, I was curious about all his medications and decided to check them out. He was also a little amused because I had not ever asked him about his medications before. Anyway, I got out my lexi-comp and started looking up doses, interactions etc. Then I came across a pretty major interaction between digoxin and verapamil. The dose of digoxin was not on the low end either. I started asking him about it and he said he takes them both together in the morning. I explained that verapamil could increase the exposure to digoxin and we all know by now about its narrow therapeutic index. Well, he had a doctor’s appointment that afternoon so I told him to make sure to ask the doctor about these two drugs and whether he should be spreading them apart. I sort of made a big deal about it so that he would actually ask. Turns out that the doctor completely waived off any concerns about the two drugs taken together and said there is nothing to worry about. He didn’t even acknowledge my dad’s concern. I sure felt like a fool. As a student pharmacist, I am learning that clinical practice is not quite the way we learn in class.