TCAs are a group of antidepressant medications used for a wide range of conditions. They can be used to treat conditions such as anxiety, panic, bulimia, and most commonly depression or chronic pain. Each medication in this class is slightly different, though they share similarities, and for that reason their side effects are different. Many cause effects such as blurred vision, dry mouth, and constipation. Still, the major mechanism by which they are dangerous is related to how this medication affects blood vessels. TCAs block an important receptor responsible for contributing to the support of blood pressure. In overdose or when a child is exposed to this type of medication, this can cause dangerously low blood pressure. With low blood pressure blood and more importantly oxygen cannot make its way to the tissues and organs it is supposed to.