In this article, we'll be looking at Xanax vs. Valium, their usages, how they work, side effects and other important pieces of information. Valium is an anti-anxiety. Jump to Side Effects - Common Valium side effects include memory problems, drowsiness, dizziness, feeling restless, muscle weakness, nausea. Read about benzodiazepines, a drug class used for treating anxiety, panic attacks anxiety and panic; seizures (convulsions), and; insomnia or trouble sleeping. benzodiazepines (for example, alprazolam [Xanax] and diazepam [Valium]) is.