Pharmacogenetics: Using Genetics to Treat Disease*
“Pharmacogenetics” by Jeanne Ting Chowning Page 2
many drugs given as chemotherapy, it is important to give a high enough dosage to prevent cancer cells from replicating, while avoiding damage to the normal tissues. Too high a drug dose can be very toxic. Dr. Ryder knows that drugs are processed in various ways in the body. They must be absorbed by the blood, distributed throughout the body’s tissues, converted or transformed into forms that are easier to eliminate, and then removed from the body. Dr. Ryder gives both girls the same dosage of the drug before leaving the hospital for the night.
While making her rounds over the next few days, Dr. Ryder sees Laura’s vital signs plummet. Her anemia has worsened; her erythrocyte count is so low that her heart function could be compromised. Her fevers are spiking, and her breathing is becoming shallow and labored. She is not eating and is being hydrated intravenously. Her condition is life-threatening. In contrast, Beth’s anemia has decreased, she is free of fever, and is actually showing signs of an appetite and boredom, good indicators of improved health. Dr. Ryder had not anticipated that the drug could act so differently in two individuals. Even as she looks at Beth’s chart, she can picture Laura’s body struggling to hold its own just two private rooms away. Dr. Ryder knows she must find out why her patients are responding so differently. But where should she start, and will she find an answer in time to help Laura?