Final answer:
When a client's prothrombin time is 20 while receiving Coumadin, notify the healthcare provider immediately due to the increased risk for bleeding. Monitoring for signs of bleeding is crucial, and pharmacogenomics may be used to optimize dosing and reduce overdose risks in the future.
Step-by-step explanation:
The appropriate nursing action when a client receiving Coumadin has a prothrombin time of 20 is option A) Notify the health care provider immediately. This is because the prothrombin time is outside the normal range of 10-14, indicating the client may be at increased risk for bleeding complications. Coumadin, also known as warfarin, is an anticoagulant that requires careful monitoring to maintain therapeutic levels while avoiding overdose and potential hemorrhage.
Pharmacogenomics, the study of how genetics impacts drug response, can assist in individualizing Coumadin dosages more accurately. It may help in predicting individual variations in drug metabolism associated with liver function differences, reducing the risk of overdose.