Pharmacists who provide medication therapy management or medication reconciliation services for patients who take more than one psychotropic drug may turn to drug monographs and drug-drug interaction (DDI) references to ensure safe use. The trouble is, DDI documentation across three major references - Clinical Pharmacology, Micromedex, and Lexicomp - is inconsistent, according to a recent study published in the Journal of the American Pharmacists Association. Researchers extracted entries for severe or major psychotropic DDIs for 102 psychotropic drugs including central nervous system stimulants, antidepressants, antipsychotics, anticonvulsants, anxiolytics-sedatives-hypnotics, and lithium. Overall, the team found 2,155 unique severe or major psychotropic DDIs listed among the references. However, only 371 DDIs were included in all three. Of the remaining DDIs, 543 were included in only two references, and 1,241 were included in just one reference.