Diazepam, also known by the brand name Valium, is a benzodiazepine used to treat anxiety, muscle spasms, and seizures. It works by enhancing the effects of the neurotransmitter GABA, leading to a calming effect on the brain and nervous system. Diazepam is fast-acting, making it ideal for acute anxiety episodes, but long-term use is generally discouraged due to the risk of dependence and tolerance. Side effects include drowsiness, dizziness, and fatigue.