Last week I went for pre-op testing for upcoming hip surgery. When I went to my doctor for clearance to have surgery my doctor said that my potassium level was 5.4 and it should be in the 3.5 - 5.2 range. He told me to stop taking lisinopril and naproxen and retest next week for potassium level. The following day I went to my cardiologist and he said he doubts lisinopril had anything to do with my high potassium. I stopped the above medicines, including Vitamin D3 1000 I.U. and baby aspirin until I get results of Potassium level and then more than likely will resume taking lisinopril and not Naproxen. Prior to taking Naproxen my potassium levels were always in range. Am I following the right protocol to lower my potassium level.