"also i forgot to mention in a previous review that timing is the key to these types of drugs. 1.5 hours is the time it takes to work for me but may vary with different people. sometimes i get to my night class early and take a klonopin well in advance so i wont be under the influence when i&#039;m driving to class. basically you have to experiment at first with the timing to get a feel of works best for you."