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.