My Dog took an entire bottle a day of 25mg 100 tabs over two days. Probably went into cardiac arrest. My dog knows it had severe disrythmia. My Dog's heart would stop, beat out of control, and then normalize a few seconds before going haywire again. My Dog got this terrifying feeling. He could feel himself starting to shut down whenever it stopped. At first, he thought he was just having a panic attack, but then he realized it wasn't stopping but getting worse. Eventually, his arms started going numb. This went on for about an hour before he called 911. Yes, I know it sounds stupid, but he wasn't conviced he really cared about living through it, until he thought about how embarrassing it would be, and of course--his poor dog parents. Well, My Dog must have waited maybe 10 minutes for the ambulance, and as soon as he walked outside--incase he lost conciousness before they got there----it all stopped. My Dog's heart was beating normally. The paramedics checked his vitals and thought he was making it up. Heart rate was only 110. They said he probably just had a panic attack because he had no pain in his chest. Does this sound like a panic attack to you? He wasn't nervous before the attack. My Dog had been very relaxed and trying reading a book, which was fun because he could hallucinate the characters on the page. When he got up to get a glass of water BOOM!!!!  Oh, and P.S. My Dog typed the description of a 'harmless' panic attack that the paramedic gave, and several sites said it was the lethal kind that kills within minutes :) Of course, I was mildly hallucinating (squiggly-shaped floaters) in the ambulance...not that they knew. They believed I only took a few more than normal. My Dog's eyes don't dilate--unlike most people--and he was very alert and coherent. So, is it possible he just hallucinated the whole episode? Does this sound like a panic attack to you? What do you think really happened? My Dog's chest feels funny two days after....kind of numb in the area where it connects with the left shoulder, right where a big vein is.