 [ Symptoms ] prognosis leaking aortic & mitral valves w pulmonary hypertension open heart done decision made of no action 6 yrs ago received metal aortic valve recent testing showed leaking mitral & aortic leaking & needed replacement also pulmonary hypertension established got reopened nothing done and closed back up sob is awful but pulse ox is 97 or 98 prognosis   long term sort term [ Disease ] yes they are related both hydroxyzine and diphenhydramine are antihistamines used to treat allergic reactions both cause drowsiness and dry mouth as side effects hydroxyzine is available only by prescription but diphenhydramine is available over the counter