Why does Valium constrict your pupils?

Valium (diazepam) is a benzodiazepine that acts as a central nervous system depressant. It can lead to pupil constriction (miOSis) due to its effects on neurotransmitter systems, particularly by enhancing the action of gamma-aminobutyric acid (GABA), which can influence the autonomic nervous system. This interaction can result in decreased sympathetic nervous system activity, leading to smaller pupils. However, pupil size can vary based on individual responses and other factors, including dosage and concurrent substances.