Hello pumpkin1, Thanks for reading my post. The protocol for treatment of ET according to many experts and my consulting physician at Mayo in Rochester is a bit long but I will try to summarize the major points.
Under age 60 with no history of clots and platelets under 1,500,000 treatment was only aspirin.
Over age 60 and platelets over 1,500,000 increased the potential for clots so hydrea was added.
Clots can happen anywhere in the body's vessels. So a clot in the eye would cause blindness, brain would cause stroke, kidney would cause kidney malfunction, heart would cause heart attack. So, to prevent clots and get the platelets down, hydrea was started. It took several months to get the platelets down to an acceptable level without lowering the other blood values to a a dangerous level.
In my case at age 60 my platelets had inched up to 1,500,000 so I started on hydrea. I had nausea for about a year but no nausea in the past 10 years.

Right now, I am on Hydrea 1000 mg 4 days a week and 1500 mg 3 days a week. My platelets hover between 500,000- 750,000. I am 70yo. I have no idea what causes the platelets to fluctuate in number and as far as I know no else does either.

I hope this was helpful. My best advise is to see an hemotology oncologist in consult with your local oncologist. In my case I have a local oncologist and I consult with a hematology oncologist at Mayo in Arizona. I believe that is why I am alive today.

Just for clarity I will say that my early consults were in Mayo in Rochester (that physician has since retired) and my latest consults were with Dr J Palmer in Arizona.