Essential thrombocythemia is a heterogenous disease from the group of Ph negativemyeloproliferative disorders. Patients with essential thrombocythemia are at risk for vascular complications (thrombosis and bleeding) and this risk depends on clinical presentation of the disease. Heterogenous is also response of this disorder to the therapy. Most of the symptomatic or otherwise high-risk patients in Czech republic are currently treated with hydroxyurea or alpha-interferon, but the probability of response to the particular agent and frequency and severity of adverse events are not possible to predict at advance. Anagrelide is a drug selectively lowering the number of platelets in patients with myeloproliferative disorders, without significant effect on other haematopoietic cell lines. This drug is valuable not only for treatment of patients with ET resistant to other agents but because its favourable profile of adverse effects and absence of leukemogenicity it is increasingly being used as a drug of first choice in patients with essential thrombocythemia. In the following review,we compare the mechanism of action and effectivity of anagrelide with those of hydroxyurea and interferon. Furthermore, we present our own experience with anagrelide in the treatment of patients with essential thrombocythemia.

        Key words: essential thrombocythemia, treatment, hydroxyurea, alpha-interferon, anagrelide.