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Neutrophil margination as a possible mechanism for verteporfin infusion-associated pain
Richard F Spaide1, Leandro Maranan
1Vitreous-Retina-Macula Consultants of New York, New York 10021, USA. VRMNY@aol.com
Purpose:
To investigate the changes in absolute neutrophil counts in patients with and without pain after verteporfin infusion.
Design:
Experimental study.
Methods:
The absolute neutrophil counts were obtained from the blood samples taken at the beginning of infusion and after the end of verteporfin infusion.
Results:
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).
Conclusions:
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.