Can panic attacks cause fainting? This is a very good question. Many people who suffer panic attacks fear that they might faint. This fear is escalated when they are doing something that requires them to be awake. Like driving or walking down the street or trying to pick up someone at the grocery store. They do not want to get embarrassed and more importantly injured or injure someone else. So they get even more worked up when they feel an attack coming on. Well the short answer to this question is, unfortunately.
First let's try to understand what's going on when a panic attack happens . Many people who fear that they might faint are hyperventalators. Meaning their breathing becomes very rapid. They are taking in way to much oxygen and not enough carbon dioxide. This makes them feel light headed. Do not confuse light headedness with false. With practice this can be controlled. It is recommended to try breathing into a paper bag or your hand to increase the amount of carbon dioxide in your lungs. Or just try to gain control over your breathing.
There is something called Vasovagal Syncope which is usually tied to blood or injury phobia. This is when someone pretty much just stops breathing at the sight of blood or injury. No breathing equals no oxygen to the brain equals fainting. Hopefully most people are aware of whether or not they have a phobia of blood or injury. If you know that you do not then you should not be worried about the fainting.
Now that being said. If fainting does actually occur there is a strong chance that there is another under condition condition other than panic disorder and you should get yourself checked out by a doctor. You could have a problem with low blood pressure or some other serious ailment that will require additional attention from your panic disorder.