Anagrelide hydrochloride is a phosphodiesterase-III inhibitor that reduces the hydrolysis of cyclic adenosine monophosphate (Cyclic AMP) and subsequently increases its intracellular concentration. Also, this drug is a platelet aggregation inhibitor that induced by ADP and collagen. Anagrelide is an oral agent that is used to treat primary thrombocythemia and secondary thrombocytosis, as well as myeloproliferative disorders (a group of slow-growing blood cancers, including chronic leukemia). The mechanism of action of Anagrelide is not fully understood but studies demonstrate that the drug selectively decrease platelet levels without a significant effect on other types of blood cells and is unique in this regard.