HEPTABARBITAL is an intermediate or short term barbiturate. It binds to the GABAA receptor at either the alpha or the beta subunit. This GABAA receptor binding decreases input resistance, depresses burst and tonic firing, especially in ventrobasal and intralaminar neurons, while at the same time increasing burst duration and mean conductance at individual chloride channels; this increases both the amplitude and decay time of inhibitory postsynaptic currents. HEPTABARBITAL was formerly used as a sedative and hypnotic drug.