My husband with Parkinson's also has anxiety associated with off periods and dystonia. He is on sertraline and trazadone also. But when he has a full-fledged panic attack, if an extra dose of Sinemet doesn't work and I can't talk him through it, the only thing we've found that works is Ativan. It's not a drug to be given lightly, but it does work for him on an emergency basis. But it's not a good solution for day to day anxiety.