Luminal is an anticonvulsant drug that is commonly used in the control of neonatal seizures and epilepsy via mediating GABAergic signalling and inhibiting glutamatergic transmission. Although it is reported that Luminal may affect the neuronal activity in the cerebral cortex and hippocampus, its impact on the hypothalamic nuclei including the paraventricular nucleus (PVN) and the supraoptic nucleus (SON) has not been elucidated. The PVN and SON are particularly important due to the release of arginine-vasopressin (AVP) which plays a crucial role in regulating cardiovascular functions, metabolism and locomotor behaviour, by their magnocellular neurons. In this study, we investigated the effect of chronic administration of Luminal (for 6 months) on the PVN and SON of male mice. We evaluated the expression of AVP by immunofluorescence and the changes in the cellular architecture by cresyl violet staining of PVN and SON. We also assessed the impact of Luminal administration on locomotor activity, which is largely influenced by AVP. Our findings indicated that chronic administration of Luminal decreased the expression of AVP in PVN and SON without significant changes in their neuronal architecture and influenced locomotor behaviour. Our findings provide novel insights into the central effect of anticonvulsant treatments on the AVP-producing neurons in the hypothalamus and could explain possible side effects on body physiology and behaviour. This may help optimize the therapeutic strategies used for seizure control.