When taking the anxiety medication Klonopin you should begin to feel the effects of the Klonopin within 30 to 60 minutes.
One dose of Klonopin should last from 6 hours to 24 hours depending on the dosage you take.
The other anxiety medications such as benzodiazepines including Ativan or Xanax take less time but Klonopin works much better especially for severe anxiety even though it can take up to an hour to take effect.