Potential subjects were accepted
into the study if they had none of the following conditions: severe or symptomatic cardiac disease or hypertension; history of bleeding disorders;
chronic history of gastric, intestinal, liver, pancreatic, or renal disease; any portion of the stomach or the intestine removed (other than an appendectomy); history of intestinal obstruction, malabsorption, or use of antacid drugs; cancer (active or use of medications for a history of cancer treatment within the past 5 y); history of
chronic alcoholism; a convulsive disorder; or abnormal results in screening blood or urine samples.