Hi
Sorry to hear of the struggle.
It's not a med I know anything about.

As my son had negative reactions to all the medications he was tried on, we used mainly natural/alternative treatments. (He was later diagnosed with Multiple Chemical Sensitivity, which the Allergist felt likely explained his intensely negative reactions to the pharma drugs)

My son's anxiety periods were really helped by Bach's Rescue Remedy which seemed to instantly calm him as well as acupuncture with a therapist knowledgeable of Tourette. He also benefited from Cognitive Behavioural Therapy, which helped both the anxiety and OCD.
A 20 minute soak in a warm Epsom Salts bath was also very helpful all round (2 cups Epsom- magnesium sulfate in the warm water)
Jasmine essential oil and chamomille tea also were helpful

Sorry not to have any other anti-anxiety meds to suggest, but I do hope you find something that will be helpful.