Been on for 8 days . Take at 8:20 a.m in morning no food allowed for 2 1/2 hrs and the throbbing headache side effect lasts from them til 5 or 530 then wanes until I take the next day same time and repeat side effect is same. Called Dr who is my cardiologist and the nurse called back and said that means its working on the vessels inclucing the heart. I had stents put in August of 2020 and have had chest pain and lower front teeth throbbing which in the past usually meant a blockage . My question is how many days do these headaches last?