Hi "Forever Young" - Regarding Klonopin - It was given to me back in 1992, I found a Psychiatrist working with a research team that specialized in this area. The Doctor quickly diagnosed me with "Severe Panic Disorder" and also a condition called "O.C.D".
Klonopin - will stay in your body the longest, and it worked very well for me since it provided "a shield of protection for the whole day" - I was having at least 2x panic attacks and 6 or more anxiety attacks during the day before, especially when driving on a freeway, or on elevator and especially in when we had company staff meetings.
Klonopin - Worked best at night to prevent "Nocturnal Panic Attacks" or "sleep terrors" - it really helped me sleep and would wake up without anxiety. I was started on the starting dosage of: .25 mg at bedtime.
The following week they started me on Prozac, which in my case tends to make me a little edgy at first but worked great once I had taken it for a month. So my Dr. bumped the dosage to .50 mg at bedtime to offset the Prozac Edgy effects.
I was slowly weaned off Klonopin - when the Prozac started working to prevent my panic attacks.
The only concern I would have with Klonopin and Valium is that they stay in your system, and you may wake up groggy - so you want to make sure you are alert before driving in the morning. I did not have this issue, the opposite for me - I was RELAXED and Anxiety Free !!
Since I have used all the main benzodiazepines - the advantage of Klonopin/Valium is the one time dosage vs taking Xanax or Ativan 3X per day and having to worry that it wear off during the day and have a panic or anxiety attack.
You mentioned you are switching from Celexa to Zoloft? Any reason why? And you were on Prozac before..? I have taken all three of these meds.
My reason for switching to different antidepressants - was the "unspoken sexual side-effects" that are very common for these type of meds...
I am currently for the last 7 years - settled back to the best meds with the fewest side effects: Prozac (Brand name - not generic) 20-40 mg per day and Valium 10 mg at night. Also have drastically increased my Omega -3 supplements to 2,000-3,000 mg per day based on new promising research that the high dosage of EPA in Omega 3 acts very similar to Prozac and other antidepressants.
I Hope this helps... Happy to share my experiences...