Follow your doctor's instructions on the bottle, this is how the drug works best. Playing around with your dosage is messing you up, just try what he prescribed and see how that works. Your body is reacting to the constant change in dosage. I take clonazepam with excellent results, but I follow the instructions completely. NEVER mix any other drugs with what you are taking without first talking to your doctor, this can be very serious and fatal. Take care...
You state that around the time you were dx'd with IBS, you also developed severe anxiety with panic attacks.
You don't say if your doctor gave you anything, at that time, to help you deal with the anxiety.
Tomorrow you are leaving for a very long flight to the US which entails no less than 6 flight changes. You say your doctor has prescribed you some clonazepam, (Klonopin) "to get you through this trip." (I take that to mean that flying makes you nervous)
While Klonopin is a very good med for the long term treatment of anxiety/panic, it normally takes a couple of weeks to reach therapeutic levels in our systems. (In other words, it needs time to build up/accumulate to work effectively) It is not USUALLY used on a prn (as needed) basis. A shorter acting benzo like Xanax is more commonly prescribed for SHORT TERM, PRN situations..............such as fear/nervousness about flying.
You tried the Klonopin at home and did not achieve any relief until you took the full 2mg dose at one time. He has prescribed that you take 1/2 a tablet, (or 1mg) every three hours.
I don't know if you'll have enough time to try a different med before you have to leave, but I would suggest trying to get hold of your doctor and tell him about your response to the Klonopin and the dosage it required for you to achieve that response. It would have been good if you'd had the time to try both the Klonopin and the Xanax and see which helped you the most. If you do not have time to experiment with different medications, talk to your doctor about the dosage of Klonopin. He may not want you taking 2mg every three hours. Make sure he is well aware of your level of fear, not that you're just a little "nervous." It's also a good idea to make the flight attendants aware of your fear. They deal with this all the time and are excellent allies if you should experience some panic during the flight.
As for the left over medication you had from a previous surgery.......my recommendation is that you flush it down the toilet but whatever you, do NOT take it on top of the Klonopin! First of all, it is over a year old and many medications can alter chemically over that time. You also have no idea if there could be an interaction problem with the two. Please be safe and don't even consider taking this med.
Try to speak with your doctor before you leave or his nurse to clarify the dosage of the Klonopin.
You'll be fine and know you're not going to be the only one on that plane who is scared!
Let me be the first to welcome you to the USA!
Peace
Greenlydia