1 mg of Klonopin should kick in and you should feel the effects of the 1 mg of Klonopin within 1 hour and the effects of Klonopin should last between 6 to 24 hours.
Be aware that Klonopin can make you sleepy so it's best to avoid driving or operating machinery if you plan to take Klonopin.
Klonopin should also not be taken with other opioid medicines because of it's cause of breathing problems (respiratory depression), coma, and even death in some cases.