By late 1981, Carpenter was using thyroid replacement medication, which she obtained using the name of Karen Burris, to increase her metabolism. She used the medication in conjunction with increased consumption of the laxatives (up to 80–90 tablets per night) upon which she had long relied, which caused food to pass quickly through her digestive tract. Despite Levenkron's treatment, including confiscation of medications that Karen had misused, her condition continued to deteriorate, and she lost more weight. Carpenter told Levenkron that she felt dizzy and that her heart was beating irregularly. Finally, in September 1982, she was admitted to Lenox Hill Hospital in New York, where she was placed on intravenous parenteral nutrition. The procedure was successful, and she gained some weight in a relatively short time, but this put a strain on her heart, which was already weak from years of improper diet. She maintained a relatively stable weight for the rest of her life.