In vivo imaging of the pharmacodynamics and pharmacokinetics of lithium.

The therapeutic efficacy of lithium for the long-term management of bipolar disorder is well recognized, along with the risk of lithium-induced toxicity. The author describes the current findings of in vivo functional neuroimaging techniques with respect to the pharmacokinetics and pharmacodynamics of lithium and their future potential to elucidate the drug distribution and neural mechanisms that produce its therapeutic effects. Brain Li nuclear magnetic resonance spectroscopy findings have disassociated postdose brain and blood lithium concentrations and suggest a pharmacokinetic basis for lithium response and nonresponse. The application of in vivo synaptic activity and neurochemical imaging is providing new knowledge related to the distributed neural activity associated with lithium response and is contributing to the critical human testing of neuroprotective and signal transduction models of lithium's therapeutic effects.