What is the treatment for thrombocytosis (elevated platelet count)?

From the Guidelines

Thrombocytosis should be treated with hydroxyurea as the first-line option, considering its effectiveness in managing symptomatic cases, as suggested by the study on chronic myelogenous leukemia 1. When considering treatment for thrombocytosis, it's crucial to differentiate between primary and secondary causes, as this distinction significantly influences the therapeutic approach.

• For primary thrombocytosis, which is often associated with bone marrow disorders, cytoreductive therapy is typically required to prevent thrombotic complications.
• Hydroxyurea is commonly recommended as the initial treatment, with dosages ranging from 500-1000 mg daily, adjusted to maintain platelet counts below 400,000/μL, thereby reducing the risk of thrombosis.
• Additionally, low-dose aspirin (81-100 mg daily) may be prescribed to further mitigate thrombotic risk, especially in patients with high-risk features.
• In cases where patients are intolerant to hydroxyurea or present with high-risk factors, alternative treatments such as anagrelide (starting at 0.5 mg twice daily) or interferon-alpha may be considered.
• For secondary thrombocytosis, which occurs as a reaction to another condition (e.g., infection, inflammation, iron deficiency), the primary focus is on treating the underlying cause, as the elevated platelet count usually normalizes once the underlying condition is resolved.
• Aspirin may be temporarily used in secondary thrombocytosis if there's an elevated risk of thrombosis.
• Platelet apheresis is typically reserved for emergency situations characterized by extreme thrombocytosis and active thrombotic events. Regular monitoring of complete blood counts and patient education on recognizing symptoms of thrombosis or bleeding are essential components of thrombocytosis management, as highlighted by the treatment options for symptomatic thrombocytosis, including hydroxyurea, antiaggregants, anagrelide, or apheresis 1.

From the FDA Drug Label

Anagrelide is a platelet reducing agent indicated for the treatment of thrombocythemia, secondary to myeloproliferative neoplasms, to reduce the elevated platelet count and the risk of thrombosis and to ameliorate associated symptoms including thrombo-hemorrhagic events. Anagrelide capsules are indicated for the treatment of patients with thrombocythemia, secondary to myeloproliferative neoplasms, to reduce the elevated platelet count and the risk of thrombosis and to ameliorate associated symptoms including thrombo-hemorrhagic events.

Treatment for Thrombocytosis: Anagrelide is indicated for the treatment of thrombocythemia, secondary to myeloproliferative neoplasms, to reduce the elevated platelet count and the risk of thrombosis and to ameliorate associated symptoms including thrombo-hemorrhagic events 2, 2, 2.

• The starting dose for adults is 0.5 mg four times a day or 1 mg twice a day.
• The starting dose for pediatric patients is 0.5 mg per day.
• Dose titration should be done to maintain target platelet counts, with a maximum dose increment of 0.5 mg/day in any one week, and not exceeding 10 mg/day or 2.5 mg in a single dose.

From the Research

Treatment Options for Thrombocytosis

Thrombocytosis, or elevated platelet count, can be treated with various approaches depending on the underlying cause and risk factors. The following are some treatment options:

• Hydroxyurea: a non-alkylating agent that can reduce the rate of vascular complications and is often used as a first-line treatment for high-risk patients 3, 4, 5
• Anagrelide: an oral antiplatelet agent that can be used as a second-line therapy for patients with high-risk essential thrombocythemia who experience intolerance or refractoriness to first-line approaches 3, 4, 6
• Interferon-alpha (IFN-alpha): a cytokine that can be used to treat high-risk patients, particularly those who are pregnant or have a history of thrombosis 3, 5
• Low-dose aspirin: can be used to prevent thrombotic complications in patients with low-risk essential thrombocythemia or those with platelet counts < 1,500 x 10(9)/L 3, 4, 5
• Phlebotomy: a procedure that involves removing blood from the body to reduce the risk of thrombosis, often used in patients with polycythemia vera 3

Risk Stratification

Risk stratification is crucial in determining the appropriate treatment approach for thrombocytosis. The following are some risk factors to consider:

• Age: patients older than 60 years are considered high-risk 3, 4, 5
• Prior thrombosis: patients with a history of thrombosis are considered high-risk 3, 4, 5
• Platelet count: patients with platelet counts > 1,500 x 10(9)/L are considered high-risk 3, 4
• Cardiovascular risk factors: patients with cardiovascular risk factors such as smoking and obesity are considered high-risk 3

Special Considerations

Special considerations should be taken into account when treating thrombocytosis in certain patient populations, such as:

• Pregnant women: IFN-alpha can be used to treat high-risk pregnant women who need treatment 3, 5
• Young patients: anagrelide can be used as a second-line therapy for young patients with high-risk essential thrombocythemia, but its use should be limited to the JAK2-mutated subgroup and exposure time should be reduced 6