Milnacipran influences the indexes of I-metaiodobenzylguanidine scintigraphy in elderly depressed patients

Abstract

Aim This study investigated whether or not and how much milnacipran influences the indexes of I-metaiodobenzylguanidine (I-MIBG) scintigraphy, early heart-to-mediastinum (H/M) ratio, delayed H/M ratio, and wash-out rate. Methods Six elderly depressed patients participated in the study. All six patients met the diagnostic criteria for a major depressive disorder. They were taking milnacipran for their depression. They needed differential diagnosis for Lewy body diseases due to their symptomatology. I-MIBG scintigraphy was performed twice for each subject, once under prescription of milnacipran and the other without prescription of milnacipran. Results Both early and delayed phase H/M ratio were significantly lower when taking milnacipran (early phase H/M ratio, P < 0.01, Cohen's d 1.62; delayed phase H/M ratio, P < 0.005, Cohen's d 1.98) than when not taking the drug. Wash-out rate (%) was significantly higher when taking milnacipran (P < 0.05, Cohen's d 2.31) than when off the drug. Conclusion Taking milnacipran substantially influences the indexes of I-MIBG scintigraphy, indicating that taking the drug possibly causes a false-positive result for Lewy body diseases diagnosis. © 2013 The Authors.