Medicine side effects

My mom was taking Avalide 300/12.5 for several years.  In September she had a stomach virus, and since then has had extremely low blood pressure, rapid pulse, shortness of breath, and swelling of her feet.  Her doctor changed her medication to Avapro 150, and the symptoms got better.  Since her feet were still swollen, he put her on 15 mg of hydrochlorothiazide along with the Avapro, and her blood pressure is low again and her pulse is fast.  She feels worn out all the time, and feels especially bad when she first gets up in the morning.  Her doctor also said she's anemic, but isn't treating that.  She also takes calcium supplements for osteoporosis and large doses of vitamin A for macular degeneration.  Anyone have any suggestions?  Thanks.