Lurasidone may cause pseudo-thrombocytopenia, report NIMHANS researchers

Ethylenediaminetetraacetic acid (EDTA)-dependent pseudothrombocytopenia (PTCP) occurs due to in vitro agglutination of platelets in the blood collection tube in the absence of clinical signs of thrombocytopenia. Instances of this condition with psychotropics such as olanzapine and valproate have been reported. For the first time ever, a research team led by Dr. Sakhardande from NIMHANS, Bengaluru has reported the incidence of PTCP with antipsychotic lurasidone. The case report was recently published in the Indian Journal of Psychiatry.

A 28-year-old physician presented to NIMHANS with a diagnosis of bipolar affective disorder-Type 2, in a moderate depressive episode. She also met diagnostic criteria for emotionally unstable personality and polysubstance use.

At the time of presentation, she was on lithium 900 mg/d and lurasidone 80 mg/d for 4 months. She was abstinent from all substances except nicotine for 4 months. A platelet count done 4 months ago was within the normal reference range.

But her present hemogram revealed persistently low platelet counts ranging from 20,000 to 30,000/uL. Total and differential white blood count, hemoglobin, and red blood counts were consistently within the normal limits. There was no history of febrile illness or recent weight loss. There were no signs of mucosal bleeding, petechiae, or purpuric patches. Tourniquet test was negative.

When no obvious cause or clinical manifestation of thrombocytopenia was found, the authors did a peripheral smear which showed adequate platelets (in clumps). A platelet count collected in a heparinized bulb revealed a count of 1,50,000/uL. Based on this, a diagnosis of PTCP was made.

Lurasidone was ineffective in alleviating depression, so was tapered and stopped. Psychotherapy was initiated. Three months later, a repeat platelet count was within the normal reference range. The Naranjo Adverse Drug Reaction Probability Scale revealed a score of 6, suggestive of a probable adverse drug reaction to lurasidone.

EDTA-associated PTCP is diagnosed when thrombocytopenia (<1,00,000) is seen when EDTA tubes are used for blood collection. This is the first instance of PTCP being described with lurasidone use. The use of an alternate anticoagulants such as citrate and heparin may help in differentiating PTCP from true thrombocytopenia.

Source: Indian Journal of Psychiatry: doi: 10.4103/indianjpsychiatry.indianjpsychiatry_625_21