Hi, I had gone through your query and understand your concerns. Postural orthostatic tachycardia syndrome (POTS, also postural tachycardia syndrome) is more specific orthostatic intolerance, in which a change from the supine position to an upright position causes an abnormally large increase in heart rate (tachycardia). People with POTS have problems maintaining homeostasis when changing position, e.g. moving from one chair to another or reaching above their heads. Many also experience symptoms when stationary or even while lying down. Metoprolol, a beta blocker, is often prescribed to treat POTS. However, it may occur some side-effects, such as bradycardia, persistent symptoms of dizziness, fainting and unusual fatigue, swelling of the hands or feet, hair loss, mental/mood changes, dyslipidemia, easy bruising or bleeding, and rash, itching, swelling, ect… I suggest you to consult a local physician, who may switch to atenolol from metoprolol for you. Hope this answers your query. If you have additional questions or follow up queries then please do not hesitate in writing to us. I will be happy to answer your queries. Wish you good health.