A client with atrial fibrillation who is receiving maintenance therapy of warfarin sodium has a prothrombin time (PT) of 35 (35) seconds and an international normalized ratio (INR) of On the basis of these laboratory values, the nurse anticipates which prescription?

Adding a dose of heparin sodium Holding the next dose of warfarinIncreasing the next dose of warfarinAdministering the next dose of warfarin

Explanation.

The normal PT is 11 to 12.5 seconds (conventional therapy and SI units). The normal INR is 2 to 3 for standard warfarin therapy, which is used for the treatment of atrial fibrillation, and 3 to 4.5 for high-dose warfarin therapy, which is used for clients with mechanical heart valves. A therapeutic PT level is 1.5 to 2 times higher than the normal level. Because the values of 35 seconds and 3.5 are high, the nurse should anticipate that the client would not receive further doses at this time. Therefore, the prescriptions noted in the remaining options are incorrect.