Neutrophil margination as a possible mechanism for verteporfin infusion-associated pain.

Abstract

To investigate the changes in absolute neutrophil counts in patients with and without pain after verteporfin infusion. Experimental study. The absolute neutrophil counts were obtained from the blood samples taken at the beginning of infusion and after the end of verteporfin infusion. Four patients in whom verteporfin infusion-related pain developed had a decrease in the absolute neutrophil counts from a preinfusion mean of 4,589/mm(3) to a postinfusion mean of 1,688/mm(3) while they had pain, as compared with preinfusion and postinfusion counts of 4,912/mm(3) and 4,111/mm(3), respectively, in five control patients having no pain, a difference in proportion that was significant (P =.027). Patients in this study with verteporfin infusion-associated pain developed neutropenia during infusion, most likely from drug-induced neutrophil margination. It is possible that medications preventing the transient neutropenia may help avert verteporfin infusion-associated pain.