Atagabalin (INNTooltip International Nonproprietary Name, USANTooltip United States Adopted Name; developmental code name PD-0200390) is a drug developed by Pfizer and related to gabapentin, which similarly binds to the α₂δ calcium channels (1 and 2). It was under development as a treatment for insomnia, but was discontinued following unsatisfactory trial results. The drug reached phase 2 clinical trials for this indication prior to the discontinuation of its development.