Klonopin (clonazepam) is a commonly used anti-anxiety medication that can cause constipation as a side effect. It works by slowing the central nervous system and reducing brain chemicals that cause anxiety, but this can also lead to drowsiness, nausea, memory loss, and other issues. Taking Klonopin may relieve anxiety symptoms within an hour but does not address the underlying causes and long-term use can have side effects like constipation.