Are there many common side effects of valium?

Yes. Valium is a long-acting medicine, and its breakdown products are active also. These can build up in your system, giving more relaxation and sedation than you might want. There can also be dizziness, memory loss, confusion, and fatigue. These effects can be more likely depending on additional other sedating medicines or substances you might be taking. Nausea can be an issue for some people too.