In observational analyses , use of ciprofloxacin and piperacillin/tazobactam predicted risk of relative thrombocytopenia ( vs. cefuroxime , RR : 2.08 [ 1.48-2 .92 ] ; 1.44 [ 1.10-1 .89 ] , respectively ) , however only ciprofloxacin were associated with a reduction in absolute platelet count ( p = 0.0005 ) .