Scary biscuits

When I was on the beach with the dogs, Marag had another wee episode  but was fine. This evening she had a full blown seizure which lasted a very scary 15 minutes.  It was frightening to watch especially when she managed to stand up and bolted through the open veranda door and was all for jumping the bannister into the neighbours garden a drop of about 10 feet. I finally managed to get her lead on and calm her down. 
The vets did full blood tests but they turned out ok. We're thinking its a bad reaction to the tick prevention  Bravecto thats causing her seizures. In which it will be in her system until August!!!
Anyway we came away with some medicines  to see if that will  help.  Poor pup.