title: Rapid-Onset Thrombocytopenia Following Piperacillin-Tazobactam Reexposure.
abstract: Drug-induced thrombocytopenia is a rare but serious adverse event that has been associated with multiple drugs including β-lactams. Although it mostly occurs with prolonged medication use, some cases of rapid-onset thrombocytopenia have been reported. We describe the case of a 69-year-old man who developed severe and immediate thrombocytopenia following reexposure to piperacillin-tazobactam in the critical care setting. He received a 6-day course of piperacillin-tazobactam for a possible pneumonia immediately after cardiac surgery. During this course of therapy, his platelet count decreased (fluctuating between 69 × 10(3) /mm(3) and 104 × 10(3) /mm(3) ) and then progressively increased after completion of the antibiotic to 340 × 10(3) /mm(3) on postoperative day 15. Ten days after the antibiotic course was completed (postoperative day 16), the patient developed new signs of infection (fever and neutrophilia), and piperacillin-tazobactam was restarted. Eight hours after reintroducing the antibiotic, his platelet count dropped from 317 × 10(3) /mm(3) to 7 × 10(3) /mm(3) . After reviewing all the medications administered to the patient as well as other potential causes of thrombocytopenia, and given the chronology of events, piperacillin-tazobactam was suspected as the most likely offending agent and was therefore replaced by meropenem on postoperative day 17. The patient's platelet count began to rise 2 days after discontinuation of piperacillin-tazobactam and reached 245 × 10(3) /mm(3) by postoperative day 30. No spontaneous bleeding or thrombosis occurred while the patient was thrombocytopenic. Use of the Naranjo Adverse Drug Reaction Probability Scale indicated a probable relationship (score of 6) between the patient's development of thrombocytopenia and piperacillin-tazobactam therapy. This case highlights the severity and swiftness in which drug-induced thrombocytopenia may present in the context of cardiac surgery.
authors.affiliation: Department of Pharmacy Services, McGill University Health Center, Montreal, Quebec, Canada.|Faculty of Pharmacy, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Van Dong
authors.initials: VD
authors.lastname: Nguyen
authors.affiliation: Department of Pharmacy Services, McGill University Health Center, Montreal, Quebec, Canada.|Faculty of Pharmacy, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Tourigny
authors.affiliation: Faculty of Pharmacy, University of Montreal, Montreal, Quebec, Canada.|Department of Pharmacy Services, Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Renaud
authors.initials: R
authors.lastname: Roy
authors.affiliation: Department of Pharmacy Services, Montreal Heart Institute, Montreal, Quebec, Canada.
authors.forename: Denis
authors.initials: D
authors.lastname: Brouillette
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D001026:Coronary Artery Bypass; D003937:Diagnosis, Differential; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000139:chemically induced* / Q000175:diagnosis; D008297:Male; D010397:Penicillanic Acid / Q000009:adverse effects / Q000031:analogs & derivatives*; D010878:Piperacillin / Q000009:adverse effects; D000077725:Piperacillin, Tazobactam Drug Combination; D011014:Pneumonia / Q000188:drug therapy; D011183:Postoperative Complications / Q000188:drug therapy; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000175:diagnosis
chemical_list: D000900:Anti-Bacterial Agents; D000077725:Piperacillin, Tazobactam Drug Combination; D010397:Penicillanic Acid; D010878:Piperacillin
keywords: adverse drug reactions; critical care; drug safety; drug-induced thrombocytopenia; piperacillin-tazobactam; platelet; thrombocytopenias