Although its not reccomended for any kind of drugs there is a bigger problem with drugs that may be harmful if the dosage is increased, sedatives are particularly suseptible to this! I would tell you to ask yout doctor but he would more then likely laugh at you!
However I think UT is a great rememdy for anxiety as it contain Dhea and melatonin two androsterones responsible for maintaining your fight or flight responses and helping to eleviate anxiety!
I cant recomment it but perhaps you could use it between doses just before you feel you need your medication and see if it eases your anxiety! Try a little at a time!
Like I said you cant ask your doctor who presribes the drug your on so you have to use your own judgement!