When teens begin to become aggressive verbally, the most common action is for parents to enter into a power struggle. When in a conflict, it is typical that when one person raises their voice the other then begins to raise theirs. Often this is done in order for each party to feel their voice is heard. Many people assume the louder person then wins, although each person continues to get louder and louder.
Sometimes the simplest action of lowering your voice can defuse an argument from escalating and stopping the fight/flight response. If this action does not end the conflict and calming your teen note that you and he/she are safe in the moment. If you and your teen are safe, take a physical step back from the situation. Our bodies have muscle memory, if you take a physical step back, your mind will soon follow with healthy behaviors previously learned or practiced. Once calm, remember to return to the conversation in order to process. If unable to have this conversation, you and your teen could benefit from writing down your feelings and discussing with your therapist for support.