From the FDA Drug Label
The probability of thrombocytopenia increases significantly at total trough valproate plasma concentrations above 110 μg/mL in females and 135 μg/mL in males.
Absence seizures themselves do not directly cause thrombocytopenia. However, the treatment of absence seizures with valproate can increase the risk of thrombocytopenia, particularly at high doses. The risk of thrombocytopenia is related to the valproate plasma concentration, with a significant increase in risk at concentrations above 110 μg/mL in females and 135 μg/mL in males 1.
From the Research
Absence seizures do not directly contribute to thrombocytopenia, but certain antiepileptic medications used to treat absence seizures can cause thrombocytopenia as a rare side effect. The relationship between absence seizures and thrombocytopenia is primarily indirect, through the side effects of medications such as valproic acid (Depakote) 2. Valproic acid, commonly used to treat absence seizures, can suppress bone marrow function, leading to reduced platelet production and, consequently, thrombocytopenia. This condition typically resolves upon discontinuation or reduction of the medication dose.
Key points to consider:
- Absence seizures and thrombocytopenia are generally unrelated conditions, with the former being a type of generalized seizure and the latter a blood disorder characterized by low platelet counts.
- Valproic acid, an antiepileptic drug, is known to cause thrombocytopenia, particularly at high serum levels (over 140 micrograms/mL) 2.
- The management of thrombocytopenia in patients with absence seizures involves monitoring platelet counts, especially during the initial months of treatment with valproic acid or other potentially thrombocytopenic medications.
- Alternative antiepileptic medications, such as ethosuximide, lamotrigine, or others, may be considered based on the specific clinical scenario and the presence of comorbid conditions or other seizure types 3.
- In cases where thrombocytopenia develops, adjusting the medication regimen, including reducing the dose or switching to a different antiepileptic drug, can help manage the condition.
Given the potential for valproic acid to induce thrombocytopenia, patients taking this medication should undergo regular blood count monitoring 2, 4. If signs of thrombocytopenia, such as unusual bruising, bleeding, or petechiae, are observed, immediate medical attention is necessary to assess the need for intervention. The choice of antiepileptic medication should be guided by the most recent and highest quality evidence, considering both efficacy in controlling seizures and the potential for adverse effects, including thrombocytopenia 3.