Z944 is an inhibitor of T-type calcium channels (IC50s = 0.050-0.160 μM for the human recombinant voltage-gated calcium (Cav) channels Cav3.1, Cav3.2, and Cav3.3). It is selective for T-type channels over the N-type Cav2.2 channel (IC50 = 11 μM), as well as the rat L-type Cav1.2, human-ether-a-go-go (hERG/Kv11.1) potassium, and human voltage-gated sodium (Nav) channel Nav1.5 (IC50s = 32, 7.8, and 100 μM, respectively). Z944 (30 mg/kg) reduces the seizure duration and the amount of time rats spend in seizures in a model of absence epilepsy. It delays seizure progression in amygdala-kindled rats but does not inhibit seizures in fully kindled rats.