If your dog is taking any medications, you should contact you veterinarian to see what the side effects are and if fainting is possibly related to the medications.

Seek Veterinarian Attention At the first sign of a fainting episode, you will want to bring your dog to your veterinarian for a full evaluation to find out what is causing. Other causes for fainting in dogs can be due to a collapsed trachea, which can cause a severe cough in the dog with gagging that can cause him or her to temporarily lose consciousness. Canine fainting is called syncope, which causes the dog to completely collapse and this can last just a few seconds up to several minutes. Small and toy breeds are more prone to the collapsed trachea problem than are larger dogs.

Many fainting spells are caused from low blood pressure, but finding out what is causing the low blood pressure is another matter entirely. Of course, seeing your dog go limp and collapse can be a frightening sight to witness.

Additionally, certain drug medications that your dog may be on can also cause a reaction that includes fainting.