From the Guidelines
The patient with thrombocytosis should continue hydroxyurea (Hydrea) while taking enoxaparin (Lovenox) 30mg subcutaneously (sub Q) daily, as the combination of these medications is often necessary to manage both the underlying condition and prevent thrombotic complications, as seen in patients with cancer who require extended anticoagulation therapy 1.
Key Considerations
- Hydroxyurea helps control platelet production in thrombocytosis by suppressing bone marrow activity, while enoxaparin is a low molecular weight heparin that prevents blood clot formation.
- The combination therapy may be prescribed to manage both the underlying condition (elevated platelet count) and prevent thrombotic complications, as supported by the NCCN-recommended dosing regimens for dalteparin in immediate VTE treatment and tinzaparin in VTE prophylaxis 1.
- However, this combination requires careful monitoring for potential bleeding risks or other side effects, particularly in patients with renal insufficiency, as enoxaparin is associated with a 2- to 3-fold increased risk of bleeding when administered in standard, unadjusted therapeutic doses to patients with severe renal insufficiency 1.
Monitoring and Precautions
- Regular blood tests to check platelet counts, hemoglobin levels, and other parameters are important while on this combination.
- If the patient has renal insufficiency, the dose of enoxaparin may need to be adjusted, as recommended by the manufacturer, to 30 mg of subcutaneous enoxaparin daily for VTE prophylaxis and 1 mg/kg subcutaneously every 24 hours for VTE treatment for patients with creatinine clearance less than 30 mL/min 1.
- Patients should be instructed to report any unusual bleeding, bruising, or other concerning symptoms to the prescribing physician immediately for guidance.
From the Research
Thrombocytosis and Anticoagulation Therapy
- Thrombocytosis is a condition characterized by an elevated platelet count, which can increase the risk of thrombotic events 2, 3, 4.
- Enoxaparin, a low molecular weight heparin, is commonly used as an anticoagulant to prevent deep vein thrombosis and pulmonary embolism 2, 3, 4, 5.
- However, enoxaparin has been associated with reactive thrombocytosis, a rare adverse drug reaction 2, 3, 4.
Management of Thrombocytosis with Hydroxyurea
- Hydroxyurea is a medication used to reduce platelet counts in patients with thrombocytosis 6.
- In a case report, a patient with essential thrombocythemia and acquired von Willebrand syndrome was treated with high-dose hydroxyurea, which effectively reduced the platelet count and minimized the risk of peri-procedural hemorrhage 6.
Interaction between Enoxaparin and Hydroxyurea
- There is limited evidence on the interaction between enoxaparin and hydroxyurea in patients with thrombocytosis 2, 3, 4.
- However, it is suggested that enoxaparin-induced reactive thrombocytosis can be managed by discontinuing enoxaparin and switching to alternative anticoagulants, such as unfractionated heparin 4.
Recommendations for Patients with Thrombocytosis on Enoxaparin and Hydroxyurea
- Patients with thrombocytosis on enoxaparin and hydroxyurea should be closely monitored for signs of thrombotic events or bleeding complications 2, 3, 6, 4.
- The decision to continue or discontinue hydroxyurea in patients taking enoxaparin should be made on a case-by-case basis, taking into account the individual patient's risk factors and medical history 6.