International Journal of Molecular Sciences Review Recent Topics on The Mechanisms of Immunosuppressive Therapy-Related Neurotoxicities Wei Zhang 1, Nobuaki Egashira 1,2,* and Satohiro Masuda 1,2 1 Department of Clinical Pharmacology and Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan 2 Department of Pharmacy, Kyushu University Hospital, Fukuoka 812-8582, Japan * Correspondence:
[email protected]; Tel.: +81-92-642-5920 Received: 29 May 2019; Accepted: 28 June 2019; Published: 29 June 2019 Abstract: Although transplantation procedures have been developed for patients with end-stage hepatic insufficiency or other diseases, allograft rejection still threatens patient health and lifespan. Over the last few decades, the emergence of immunosuppressive agents such as calcineurin inhibitors (CNIs) and mammalian target of rapamycin (mTOR) inhibitors have strikingly increased graft survival. Unfortunately, immunosuppressive agent-related neurotoxicity commonly occurs in clinical practice, with the majority of neurotoxicity cases caused by CNIs. The possible mechanisms through which CNIs cause neurotoxicity include increasing the permeability or injury of the blood–brain barrier, alterations of mitochondrial function, and alterations in the electrophysiological state. Other immunosuppressants can also induce neuropsychiatric complications. For example, mTOR inhibitors induce seizures, mycophenolate mofetil induces depression and headaches, methotrexate affects the central nervous