I'll put my two pennies in for what evers worth!
But I'm for changing this behavior and NOT medicating each "crisis".
It will take at least half hour start to "finish" with medication...first finding the med, administering, then waiting for blood levels to peak (20 mins minimum) the hoping the medication helps.
I think this would be hard to deal with each and every buzziebee-buzzing!
What seems better for all involved is having the dog not react with such fears/phobia's instead of having to medicate each "incident".
Perhaps just ask Cesare Malone this question....see his take on this.

Our neighbors dog, Toby, a Berienese Mt Dog...huge dog....has an extreme phobia to T-storms...a rareity around our neck of the woods.
But we when we do have one...usually see them coming miles away.
Toby comes to my home, acres away and seeks me out to give him comfort.
He's so strong and has broken down our front door when he broke in late one night...talk about freaking out!
I don't know who was freaked out most...me for thinking a robber was coming to get me...or Toby desperate to get inside my house so I could comfort him.
He's done so much damage many times.
Now they give him Benedryl....same doseage they give humans.
I use this for sleep aid and was told by a doctor is also perscribed instead of meds such as Xanex or Valium to those who're having stress or anxiety issues.
Somehow I don't see how this could work better for such....but oh well!
They give Toby a hefty dose but we don't see any changes regarding his freaking out...He's just groggy-freaking! Poor guy!
Hope this helps. Cheryl