Primary Thrombocythemia
                
This condition is considered less harmful today than in the past, and its outlook often is good. People who have no signs or symptoms don't need treatment, as long as the condition remains stable.
                
Taking aspirin may help people who are at risk for blood clots (aspirin thins the blood). However, talk with your doctor about using aspirin because it can cause bleeding.
                
Doctors prescribe aspirin to most pregnant women who have primary thrombocythemia. This is because it doesn't have a high risk of side effects for the fetus.
                
Some people who have primary thrombocythemia may need medicines or medical procedures to lower their platelet counts.
                
Medicines To Lower Platelet Counts
                
You may need medicines to lower your platelet count if you:
                
Have a history of blood clots or bleeding
                
Have risk factors for heart disease, such as high blood cholesterol, high blood pressure, or diabetes
                
Are older than 60
                
Have a platelet count over 1 million
                
You'll need to take these medicines throughout your life.
                
Hydroxyurea. This platelet-lowering medicine is used to treat cancers and other life-threatening diseases. Hydroxyurea most often is given under the care of doctors who specialize in cancer or blood diseases. Patients on hydroxyurea are closely monitored.
                
Currently, hydroxyurea plus aspirin is the standard treatment for people who have primary thrombocythemia and are at high risk for blood clots.
                
Anagrelide. This medicine also has been used to lower platelet counts in people who have thrombocythemia. However, research shows that when compared with hydroxyurea, anagrelide has worse outcomes. Anagrelide also has side effects, such as fluid retention, palpitations (pal-pih-TA-shuns), arrhythmias (ah-RITH-me-ahs), heart failure, and headaches.
                
Interferon alfa. This medicine lowers platelet counts, but 20 percent of patients can't handle its side effects. Side effects include a flu-like feeling, decreased appetite, nausea (feeling sick to the stomach), diarrhea, seizures, irritability, and sleepiness.
                
Doctors may prescribe this medicine to pregnant women who have primary thrombocythemia because it's safer for a fetus than hydroxyurea and anagrelide.
                
Plateletpheresis
                
Plateletpheresis (PLATE-let-fe-REH-sis) is a procedure used to rapidly lower your platelet count. This procedure is used only for emergencies. For example, if you're having a stroke due to primary thrombocythemia, you may need plateletpheresis.
                
An intravenous (IV) needle that's connected to a tube is placed in one of your blood vessels to remove blood. The blood goes through a machine that removes platelets from the blood. The remaining blood is then put back into you through an IV line in one of your blood vessels.
                
One or two procedures might be enough to reduce your platelet count to a safe level.
                
Secondary Thrombocytosis
                
Secondary thrombocytosis is treated by addressing the condition that's causing it.
                
People who have secondary thrombocytosis usually don't need platelet-lowering medicines or procedures. This is because their platelets usually are normal (unlike in primary thrombocythemia).
                
Also, secondary thrombocytosis is less likely than primary thrombocythemia to cause serious problems related to blood clots and bleeding.